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Stehr, Jan Eric, Xingjun Wang, Stanislav Filippov, et al. "Defects in N, O and N, Zn implanted ZnO bulk crystals." Linköpings universitet, Funktionella elektroniska material, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-91343.
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Comprehensive characterization of defects formed in bulk ZnO single crystals co-implanted with N and Zn as well as N and O atoms is performed by means of optically detected magnetic resonance (ODMR) complemented by Raman and photoluminescence (PL) spectroscopies. It is shown that in addition to intrinsic defects such as Zn vacancies and Zn interstitials, several N-related defects are formed in the implanted ZnO. The prevailed configuration of the defects is found to depend on the choices of the co-implants and also the chosen annealing ambient. Specifically, co-implantation with O leads to the formation of (i) defects responsible for local vibrational modes at 277, 511, and 581 cm−1; (ii) a N-related acceptor with the binding energy of 160 ± 40 meV that is involved in the donor-acceptor pair emission at 3.23 eV; and (iii) a deep donor and a deep NO acceptor revealed from ODMR. Activation of the latter defects is found to require post-implantation annealing in nitrogen ambient. None of these defects are detected when N is co-implanted with Zn. Under these conditions, the dominant N-induced defects include a deep center responsible for the 3.3128 eV PL line, as well as an acceptor center of unknown origin revealed by ODMR. Formation mechanisms of the studied defects and their role in carrier recombination are discussed.<br><p>Funding Agencies|Swedish Research Council|621-2010-3971|</p>
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Доброжан, Олександр Анатолійович, Александр Анатольевич Доброжан, Oleksandr Anatoliiovych Dobrozhan та ін. "Порівняння оптичних втрат у сонячних елементах на основі гетеропереходів n-ito(zno)/n-cds(n-zns, znse)/p-czts". Thesis, Сумський державний університет, 2016. http://essuir.sumdu.edu.ua/handle/123456789/46239.
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Опанасюк, Анатолій Сергійович, Анатолий Сергеевич Опанасюк, Anatolii Serhiiovych Opanasiuk та ін. "Моделювання фізичних процесів у напівпровідникових сонячних елементах на основі гетеропереходів n-ITO(ZnO)/n-CdS(n-ZnS, ZnSe)/p-CZTS". Thesis, Сумський державний університет, 2018. http://essuir.sumdu.edu.ua/handle/123456789/67813.
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Перспективним способом використання сонячної енергії є її перетворення в електричну, використовуючи сонячні елементи (СЕ), зокрема тонкоплівкові прилади типу “superstrate”, які мають багатошарову конструкцію. На теперішній час найбільш поширені СЕ першого та другого поколінь на основі поглинальних шарів Si, CdTe, GaAs, Cu(In1-x,Gax)(S1-xSex)2, які демонструють ефективність більшу за
20 %.
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Schein, Friedrich-Leonhard, Markus Winter, Tammo Böntgen, Wenckstern Holger von, and Marius Grundmann. "Highly rectifying p-ZnCo2O4/n-ZnO heterojunction diodes." American Institute of Physics, 2014. https://ul.qucosa.de/id/qucosa%3A31194.
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We present oxide bipolar heterojunction diodes consisting of p-type ZnCo2O4 and n-type ZnO
fabricated by pulsed-laser deposition. Hole conduction of ZnCo2O4 (ZCO) was evaluated by Hall
and Seebeck effect as well as scanning capacitance spectroscopy. Both, ZCO/ZnO and ZnO/ZCO
type heterostructures, showed diode characteristics. For amorphous ZCO deposited at room
temperature on epitaxial ZnO/Al2O3 thin films, we achieved current rectification ratios up to
2x1010, ideality factors around 2, and long-term stability.
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Опанасюк, Анатолій Сергійович, Анатолий Сергеевич Опанасюк, Anatolii Serhiiovych Opanasiuk та ін. "Вплив оптичних і рекомбінаційних втрат на ефективність сонячних елементів на основі гетеропереходів n-ITO(ZnO)/n-CdS(ZnS,ZnSe)/p-CZTS". Thesis, Астропринт, 2016. http://essuir.sumdu.edu.ua/handle/123456789/46081.
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Згідно з прогнозами з середини XXI століття сонячна енергетика стане домінуючим джерелом енергії людства. У наш час як перспективна заміна традиційним поглинаючим шарам тонкоплівкових сонячних елементів (СЕ) розглядається чотирикомпонентна сполука Cu2ZnSnS4 (CZTS), яка має оптимальну для перетворення сонячної енергії ширину забороненої зони (Eg = 1,5 eВ) та р-тип провідності. Віконним матеріалом у такому СЕ тардиційно виступає CdS, а фронтальним контактом ITO. Альтернативою відомим СЕ є конструкції з вікном з ZnS або ZnSe та струмознімальним шаром ZnO:Al. За оцінками ефективність тонкоплівкових СЕ з поглинаючим шаром CZTS складає 25-30 %. Однак ККД реальних СЕ не перевищує 12,7 %. Різниця між теоретичними передбаченнями та отриманими значеннями ефективності приладів пояснюється оптичними, електричними та рекомбінаційними втратами. Метою даного дослідження було визначення та порівняння оптичних та рекомбінаційних втрат у СЕ, що мають конструкцію n-ITO(n-ZnO)/n-CdS(n-ZnS.n-ZnSe)/p-CZTS/тильний металевий контакт.
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Gu, Qilin. "Hydrogen peroxide treatment induced rectifying behavior of Au/n-ZnO contact." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/HKUTO/record/B39558344.
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顧啟琳 and Qilin Gu. "Hydrogen peroxide treatment induced rectifying behavior of Au/n-ZnO contact." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B39558344.
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Liu, Huiyong. "Investigation of doped ZnO by Molecular Beam Epitaxy for n- and p-type Conductivity." VCU Scholars Compass, 2012. http://scholarscompass.vcu.edu/etd/393.
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This dissertation presents an investigation of the properties, especially the electrical properties, of doped ZnO films grown by plasma-assisted molecular beam epitaxy (MBE) under different conditions. The interest in investigating ZnO films is motivated by the potential of ZnO to replace the currently dominant ITO in industries as n-type transparent electrodes and the difficulty in achieving reliable and reproducible p-type ZnO. On the one hand, n-type ZnO heavily doped with Al or Ga (AZO or GZO) is the most promising to replace ITO due to the low cost, abundant material resources, non-toxicity , high conductivity, and high transparency. On the other hand, ZnO doped with a large-size-mismatched element of Sb (SZO) or co-doped with N and Te exhibits the possibility of achieving p-type ZnO. In this dissertation, the effects of MBE growth parameters on the properties of GZO have been investigated in detail. The ratio of oxygen to metal (Zn+Ga) was found to be critical in affecting the structural, electrical, and optical properties of GZO layers as revealed by x-ray diffraction (XRD), transmission electron microscopy (TEM), Hall measurement, photoluminescence (PL), and transmittance measurements. Highly conductive (~2×10-4 Ω-cm) and transparent GZO films (> 90% in the visible spectral range) were achieved by MBE under metal-rich conditions (reactive oxygen to incorporated Zn ratio < 1). The highly conductive and transparent GZO layers grown under optimized conditions were applied as p-side transparent electrodes in InGaN-LEDs, which exhibited many advantages over the traditional thin semi-transparent Ni/Au electrodes. The surface morphologies of GaN templates were demonstrated to be important in affecting the structural and electrical properties of GZO layers. In those highly conductive and transparent GZO layers with high-quality crystalline structures, studies revealed ionized impurity scattering being the dominant mechanism limiting the mobility in the temperature range of 15-330 K, while polar optical phonon scattering being the mechanism responsible for the temperature-dependence for T>150 K. The majority Sb ions were found to reside on Zn sites instead of O sites for lower Sb concentrations (~0.1 at.%), which can lead to a high electron concentration of above 1019 cm-3 along with a high electron mobility of 110 cm2/V-s at room temperature. The reduction in electron concentration and mobility for higher Sb concentrations (~1 at.%) was caused by the deterioration of the crystalline quality. ZnO co-doped with N and Te was also studied and the advantages of the co-doping technique and problems in achieving p-type conductivity are discussed.
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Elsharif, Zainelabdin Ahmed ELtahir. "Lighting and Sensing Applications of Nanostructured ZnO, CuO and Their Composites." Doctoral thesis, Linköpings universitet, Fysik och elektroteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-85111.
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Low dimensional nanostructures of zinc oxide (ZnO), cupric oxide (CuO), and their composite nanostructures possess remarkable physical and chemical properties. Fundamental understanding and manipulation of these unique properties are crucial for all potential applications. Integration of nanostructured ZnO and CuO and their hybrid composites may play a significant role in the existing technology while paving the way for new exciting areas. Solution based low temperature synthesis of ZnO and CuO nanostructures have attracted extensive research efforts during the last decade. These efforts resulted in a plenteous number of nanostructures ranging from quantum dots into very complex three dimensional nanomaterials. Among the various low temperature synthesis methods the hydrothermal technique became one of the most popular approaches. The use of hydrothermal approach enabled the synthesis of diversity of nanomaterials on conventional and nonconventional substrates such as metals, glass, plastic and paper etc. The primary objectives of this thesis are to study and understand the characteristics of nanostructured ZnO, CuO, and their hybrid composites synthesized at low temperature. Likewise, the hybrid composites were successfully utilized to fabricate light emitting diodes and sensors. This thesis is organized into three major parts. In the beginning the synthesis and characterization of nanostructured ZnO, CuO, and their composite nanostructures are elaborated. Efforts have been made to understand the selective assembly of hierarchical CuO nanostructures on ZnO nanorods and to correlate it to the observed unique properties of the CuO/ZnO composite nanostructures. In the second part of the thesis fabrication, characterization, and device application of ZnO/p-polymer hybrid light emitting diode (HyLEDs) on flexible substrates are presented. In particular single and blended p-type light emissive polymers were controllably developed for potential greener and cheaper white light emitters. It was found that the HyLEDs exhibited rectifying diode characteristics together with white light emission covering the entire visible range. In the third part, pH and relative humidity sensing applications of CuO nanoflowers, and CuO/ZnO nanocorals, respectively, are described. A pH sensor based on CuO nanoflowers demonstrated good sensitivity and reproducibility over a wide range of pH. By taking the advantages of the selective growth of CuO nanostructures on ZnO nanorods and their naturally formed p-n heterojunction the realization of high sensitivity humidity sensor was achieved. The humidity sensor fabricated from the CuO/ZnO nanocorals displayed the highest sensitivity factor reported so far for its constituent materials; along with reasonably fast dynamic responses. A brief outlook into future challenges and opportunities are also presented in the last part of the thesis.<br>Nanophotonics
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Poschenrieder, Margarethe. "Eigenschaften von gesputterten n+-ZnO/c-Si-Heterokontakten Transport, Grenzfläche und Bandanpassung /." [S.l.] : [s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=962360937.
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GADE, RAVICHANDRA REDDY. "Comparison of delta and uniform doped p-type and n-type ZnO films." Youngstown State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1443205675.
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Herring, Natalie. "Formation Mechanisms and Photocatalytic Properties of ZnO-Based Nanomaterials." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/494.
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Zinc Oxide (ZnO) is one of the most extensively studied semiconductors because of its unique properties, namely, its wide band gap (3.37 eV) and high excitation binding energy (60 meV). These properties make ZnO a promising material for uses in a broad range of applications including sensors, catalysis and optoelectronic devices. The presented research covers a broad spectrum of these interesting nanomaterials, from their synthesis and characterization to their use as photocatalyts. A new synthetic approach for producing morphology controlled ZnO nanostructures was developed using microwave irradiation (MWI). The rapid decomposition of zinc acetate in the presence of a mixture of oleic acid (OAC) and oleylamine (OAM) results in the formation of hexagonal ZnO nanopyramids and ZnO rods of varying aspect ratios. The factors that influence the morphology of these ZnO nanostructures were investigated. Using ligand exchange, the ZnO nanostructures can be dispersed in aqueous medium, thus allowing their use as photocatalysts for the degradation of malachite green dye in water. Photocatalytic activity is studied as a function of morphology; and, the ZnO nanorods show enhanced photocatalytic activity for the degradation of the dye compared to hexagonal ZnO nanopyramids. After demonstrating the catalytic activity of these ZnO nanostructures, various ways to enhance photocatalytic activity were studied by modification of this MWI method. Photocatalytic activity is enhanced through band gap modulation and the reduction of electron-hole recombination. Several approaches were studied, which included the incorporation of Au nanoparticles, N-doping of ZnO, supporting ZnO nanostructures on reduced graphene oxide (RGO), and supporting N-doped ZnO on N-doped RGO. ZnO-based nanostructures were studied systematically through the entire process from synthesis and characterization to their use as photocatalysis. This allows for a thorough understanding of the parameters that impact these processes and their unique photocatalytic properties.
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Sellappan, Raja. "Light emitting diodes based on n-type ZnO nanorods and p-type organic semiconductors." Thesis, Linköping University, Department of Science and Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11197.
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<p>The aim of this thesis work was to fabricate a hybrid LED using organic-inorganic ZnO materials. The goal of the project was to get an efficient white light emission from zinc oxide (ZnO) nanorods active layer. Since most of the organic materials are good for hole mobility and most of the inorganic materials are good for electron mobility, it is possible to fabricate a high performance heterostructure electroluminescence device from organic-inorganic materials. This thesis work was an attempt towards fabricating such a high electroluminescence LED from hybrid materials in which polymer acts as a p-type material and ZnO acts as a n-type material. The growth mechanism of ZnO nanorods using low-temperature aqueous solution method has been studied and nanorods (NRs) growth was examined with scanning electron microscope (SEM). Optimum hole injection polymers have been studied. Finally, the fabricated device was characterized using parameter analyzer. The fabricated device worked as a diode i.e. it rectified current as expected and the desirable light emission has almost been achieved.</p>
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Hussain, Babar. "Development of n-ZnO/p-Si single heterojunction solar cell with and without interfacial layer." Thesis, The University of North Carolina at Charlotte, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10258481.
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<p> The conversion efficiency of conventional silicon (Si) photovoltaic cells has not been improved significantly during last two decades but their cost decreased dramatically during this time. However, the higher price-per-watt of solar cells is still the main bottleneck in their widespread use for power generation. Therefore, new materials need to be explored for the fabrication of solar cells potentially with lower cost and higher efficiency. The n-type zinc oxide (n-ZnO) and p-type Si (p-Si) based single heterojunction solar cell (SHJSC) is one of the several attempts to replace conventional Si single homojunction solar cell technology. There are three inadequacies in the literature related to n-ZnO/p-Si SHJSC: (1) a detailed theoretical analysis to evaluate potential of the solar cell structure, (2) inconsistencies in the reported value of open circuit voltage (VOC) of the solar cell, and (3) lower value of experimentally achieved VOC as compared to theoretical prediction based on band-bending between n-ZnO and p-Si. Furthermore, the scientific community lacks consensus on the optimum growth parameters of ZnO. </p><p> In this dissertation, I present simulation and experimental results related to n-ZnO/p-Si SHJSC to fill the gaps mentioned above. Modeling and simulation of the solar cell structure are performed using PC1D and AFORS-HET software taking practical constraints into account to explore the potential of the structure. Also, unnoticed benefits of ZnO in solar cells such as an additional antireflection (AR) effect and low temperature deposition are highlighted. The growth parameters of ZnO using metal organic chemical vapor deposition and sputtering are optimized. The structural, optical, and electrical characterization of ZnO thin films grown on sapphire and Si substrates is performed. Several n-ZnO/p-Si SHJSC devices are fabricated to confirm the repeatability of the VOC. Moreover, the AR effect of ZnO while working as an n-type layer is experimentally verified. The spatial analysis for thickness uniformity and optical quality of ZnO films is carried out. These properties turn out to play a fundamental role in device performance and so far have been overlooked by the research community. Three different materials are used as a quantum buffer layer at the interface of ZnO and Si to suppress the interface states and improve the VOC. The best measured value of VOC of 359 mV is achieved using amorphous-ZnO (a-ZnO) as the buffer layer at the interface. Finally, supplementary simulations are performed to optimize the valence-band and conduction-band offsets by engineering the bandgap and electron affinity of ZnO. </p><p> After we published our initial results related to the feasibility of n-ZnO/p-Si SHJSC [Sol. Energ. Mat. Sol. Cells 139 (2015) 95–100], different research groups have fabricated and reported the solar cell performance with the best efficiency of 7.1% demonstrated very recently by Pietruszka et al. [Sol. Energ. Mat. Sol. Cells 147 (2016) 164–170]. We conclude that major challenge in n-ZnO/p-Si SHJSC is to overcome Fermi-level pinning at the hetero-interface. A potential solution is to use the appropriate material as buffer layer which is confirmed by observing an improvement in VOC using a-ZnO at the interface as buffer layer. Once the interface quality is improved and the experimental value of VOC matched the theoretical prediction, the n-ZnO/p-Si SHJSC can potentially have significant contribution in solar cells industry.</p>
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Lubuna, Beegum Shafeek. "Organic-Inorganic Hetero Junction White Light Emitting Diode : N-type ZnO and P-type conjugated polymer." Thesis, Linköping University, Department of Science and Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11195.
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<p>The purpose of this thesis work is to design and fabricates organic-inorganic hetero junction White Light Emitting Diode (WLED). In this WLED, inorganic material is n- type ZnO and organic material is p-type conjugated polymer. The first task was to synthesise vertically aligned ZnO nano-rods on glass as well as on plastic substrates using aqueous chemical growth method at a low temperature. The second task was to find out the proper p- type organic material that gives cheap and high efficient WLED operation. The proposed polymer shouldn’t create a high barrier potential across the interface and also it should block electrons entering into the polymer. To optimize the efficiency of WLED; charge injection, charge transport and charge recombination must be considered. The hetero junction organic-inorganic structures have to be engineered very carefully in order to obtain the desired light emission. The layered structure is composed of p-polymer/n-ZnO and the recombination has been desired to occur at the ZnO layer in order to obtain white light emission. Electrical characterization of the devices was carried out to test the rectifying properties of the hetero junction diodes.</p><p>iv</p>
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Somhlahlo, Nomabali Nelisiwe. "A Hall-effect study of as-grown and hydrogenerated n-type ZnO layers grown by MOCVD." Thesis, Nelson Mandela Metropolitan University, 2006. http://hdl.handle.net/10948/444.
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A series of as-grown ZnO layers have been electrically characterised by the temperature dependent (20 – 300 K) Hall-effect technique. The ZnO layers were grown by metal organic chemical vapour deposition (MOCVD) on glass substrates under various growth conditions. The temperature dependent Hall-effect technique produced mobility and carrier concentration measurements. These measurements were found to be reproducible and reliable. The carrier concentration data for the layers was fitted by the charge balance equation to accurately determine the donor level and corresponding donor concentration as well as the acceptor concentration for each sample. The measured donor levels were found to vary from sample to sample and there is evidence from the results that the variations are related to the differing growth conditions of the layers. The mobility data was also fitted to establish the dominant electron scattering mechanisms in the layers. The dominant scattering mechanisms were found to vary from sample to sample. For most of the layers studied, the dominant scattering mechanism was found to be both the ionised impurity scattering at low temperatures (20 – 100 K) and grain boundary scattering at higher temperatures (100 – 300 K). The effects of exposing the ZnO layers to hydrogen plasma were also investigated by the temperature dependent Hall-effect technique. Findings indicate that hydrogen is readily incorporated in ZnO, leading always to an increased carrier concentration. It was further noted that incorporating hydrogen into ZnO in some layers increased the mobility while in other layers it caused a decrease in the mobility. The hydrogenated samples were subsequently annealed at 600 °C for 1 hour in argon ambient resulting in the carrier concentration reducing to its original value. This effect is attributed to hydrogen diffusing out of ZnO.
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Hadouchi, Warda. "Etude de l'utilisation du ZnO comme contact de type n dans des dispositifs photovoltaïques à base de pérovskite hybride." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLX012/document.
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Les cellules solaires pérovskites hybrides ont marqué le monde du photovoltaïque avec une augmentation spectaculaire des rendements durant ces quatre dernières années. Avec des rendements dépassant 20% à l’heure actuelle, ce type de cellules suscite une attention particulière dans le monde scientifique. Dans l’architecture de la cellule solaire pérovskite, le TiO2 est l’oxyde le plus utilisé comme matériau collecteur d’électrons. Cette couche d’oxyde joue un rôle important dans la cellule, cependant le procédé d’élaboration du TiO2 requiert une étape de recuit à haute température. En plus des coûts élevés de production qu’elle implique, son utilisation exclut son application aux substrats sensibles aux hautes températures tels que les substrats plastiques flexibles par exemple.Cette thèse est centrée sur le remplacement du TiO2 par le ZnO en tant que couche collectrice d’électrons et bloqueuse de trous. Ce matériau représente une alternative intéressante en raison de ces propriétés comparables et même supérieures à celles du TiO2. L’intérêt du choix du ZnO réside dans sa simplicité de mise en œuvre. Ce matériau peut en effet être synthétisé à basse température (<100°C) et sous différentes structures. Dans cette étude nous avons fait le choix de considérer les croissances de ZnO par voie électrochimique et par pulvérisation cathodique. Dans des conditions de dépôts optimisées des couches de pérovskite et de ZnO, des rendements record de 14.2% et 9.7% ont été obtenus dans des architectures plane et nanostructurée respectivement<br>Perovskite solar cells have marked the photovoltaic world with a spectacular increase of efficiencies over the last four years. With efficiencies exceeding 20%, this type of solar cells attracts a particular attention in the photovoltaic field. In the standard perovskite solar cell stack, TiO2 is used as an electron-collecting layer. This oxide layer plays an important role in the cell, however, its growth process requires a high temperature annealing step. In addition to the high production costs involved, its use also exclude its application to temperatures sensitive substrates such as flexible plastic materials.This thesis focuses on the replacement of the TiO2 bilayer by a ZnO electron-collecting and hole-blocking layer. We consider ZnO as an alternative to its comparable and even superior properties. One of the interests of the choice of ZnO lies in its simplicity of implementation and the possibility to synthesize it at low temperature (<100°C) and under different structures. The ZnO is here synthesized by electrochemical way and sputtering process. Under optimized deposition conditions of perovskite and ZnO layers, record efficiencies of 14.2% and 9.7% have been obtained in planar and nanostructured architecture respectively
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Ishida, Yukiaki, Atsushi Fujimori, Hiromichi Ohta, Masahiro Hirano, and Hideo Hosono. "Potential profiling of the nanometer-scale charge-depletion layer in n-ZnO/p-NiO junction using photoemission spectroscopy." American Institute of Physics, 2006. http://hdl.handle.net/2237/8768.
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Brochen, Stéphane. "Propriétés électriques du ZnO monocristallin." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00872067.
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L'oxyde de zinc ZnO, est un semiconducteur II-VI très prometteur pour les applications en opto-électronique dans le domaine UV, notamment pour la réalisation de dispositifs électroluminescents (LED). Les potentialités majeures du ZnO pour ces applications résident notamment dans sa forte liaison excitonique (60 meV), sa large bande interdite directe (3.4 eV), la disponibilité de substrats massifs de grand diamètre ainsi que la possibilité de réaliser des croissances épitaxiales de très bonne qualité en couches minces ou nano structurées (nanofils). Néanmoins, le développement de ces applications est entravé par la difficulté de doper le matériau de type p. L'impureté permettant d'obtenir une conductivité électrique associée à des porteurs de charges positifs (trous), et donc la réalisation de jonctions pn à base de ZnO, n'a pas encore été réellement identifiée. C'est pourquoi une des étapes préliminaires et nécessaires à l'obtention d'un dopage de type p fiable et efficace, réside dans la compréhension du dopage résiduel de type n, ainsi que des phénomènes de compensation et de passivation qui sont mis en jeu au sein du matériau. La maîtrise de la nature des contacts (ohmique ou Schottky) sur différentes surfaces d'échantillons de ZnO nous a permis dans ce but de mettre en œuvre à la fois des mesures de transport (résistivité et effet Hall) et des mesures capacitives (capacité-tension C(V), Deep Level Transient Spectroscopy (DLTS) et Spectroscopie d'admittance).Dans un premier temps, nous avons donc cherché à comprendre de manière approfondie les propriétés électriques du ZnO massif. Nous avons ainsi étudié le rôle des défauts profonds et peu profonds sur la conductivité des échantillons, aux travers de différents échantillons massifs obtenus par synthèse hydrothermale ou par croissance chimique en phase vapeur. Nous avons également étudié l'impact de la température de recuits post-croissance, sur les propriétés de transport des échantillons. A la lumière des résultats obtenus sur le dopage résiduel de type n des échantillons de ZnO massifs, nous avons ensuite procédé à différents essais de dopage de type p du ZnO par implantation ionique d'azote et par diffusion en ampoule scellée d'arsenic. L'impureté azote a été choisie dans le cadre d'une substitution simple de l'oxygène qui devrait permettre de créer des niveaux accepteurs dans la bande interdite du ZnO. Nous avons également étudié l'impureté arsenic, qui selon un modèle théorique peut former un complexe qui permet d'obtenir un niveau accepteur plus proche de la bande de valence que le niveau. Outres les études réalisées sur les échantillons de ZnO massif et les essais de dopage de type p, nous avons également étudié les propriétés électriques d'échantillons de ZnO monocristallins sous forme de couches minces obtenues par croissance en phase vapeur d'organométalliques, dopées intentionnellement ou non. Les corrélations entres les mesures SIMS et C(V) nous ont permis notamment de mettre en évidence une diffusion et un rôle très importante de l'aluminium sur les propriétés électriques des couches minces de ZnO épitaxiées sur substrat saphir.Dans le cadre de cette thèse nous avons réussi à clarifier les mécanismes du dopage de type n, intentionnel ou non intentionnel, dans le ZnO monocristallin. Nous avons également identifié les impuretés et les paramètres de croissance importants permettant d'obtenir un dopage résiduel de type n le plus faible possible dans les couches épitaxiées. Cette maitrise du dopage résiduel de type n est une étape préliminaire indispensable aux études de dopage de type p car elle permet de minimiser la compensation des accepteurs introduits intentionnellement. Cette approche du dopage sur des couches minces de ZnO dont le dopage résiduel de type n est très faible apparait comme une voie très prometteuse pour surmonter les problèmes d'obtention du dopage de type p.
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Kwiatkowski, Maciej. "ZnO(core)/TiO2(shell) composites : influence of TiO2 microstructure, N-doping and decoration with Au nanoparticles on photocatalytic and photoelectrochemical activity." Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCK046/document.
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Le but de la thèse est d'étudier l'influence de la microstructure des composites ZnO/TiO2 sur leurs propriétés dans la dégradation photocatalytique des polluants organiques et dans l'oxydation de l'eau photoassistée. Pour réaliser cette étude, nous avons choisi la conception basée sur des nano bâtonnets ZnO supportés sur une électrode de verre recouverte d'ITO (Indium Tin Oxide). Les nano bâtonnets de ZnO ont ensuite été recouverts d'une couche de TiO2 dans différentes conditions. La composition et la microstructure des composites ZnO(cœur)/TiO2(coquille) ont été modifiées dans le but d'élucider comment ces paramètres influencent leur activité photocatalytique. La couche TiO2 de morphologie différente (discontinue ou compacte) a été élaborée. Nous avons montré que le composite contenant la couche de TiO2 discontinue possède une activité plus élevée dans la dégradation de MB et dans l'oxydation de H2O sous 400 nm. Cette photoactivité améliorée a été attribuée à une meilleure accessibilité pour les réactifs de l'interface ZnO/TiO2 à travers la couche de TiO2. Aussi nous avons pu améliorer l'activité des composites sous la lumière visible. Dans ce but, les composites constitués de nano bâtonnets de ZnO supportés sur ITO ont été recouverts de TiO2 dopé à l'azote et décorés de nanoparticules d'or. Il a été trouvé que même une faible charge d'or (0,37% at.) permet une augmentation de 60% de la vitesse de décoloration photocatalytique du MB sous la lumière visible par rapport à l'échantillon sans or en raison de l'effet plasmonique. Un dopage simultané à l'azote et à l'or a permis également de multiplier par trois le photocourant dans l'oxydation photoassistée de l'eau<br>The aim of the thesis is to study the influence of microstructure of ZnO/TiO2 composites on their properties in photocatalytic degradation of organic pollutants, and in photoassisted water oxidation. To realize such study we chose the design based on ZnO nanorods supported on ITO (Indium Tin Oxide)-coated glass electrode. The ZnO nanorods were then covered with a layer of TiO2 under different conditions. The composition and microstructure of the obtained ZnO(core)/TiO2(shell) composites were modified in the aim to elucidate how these parameters influence their photocatalytic activity. The results of studies lead to elaboration of two most distinctive variants of sol-gel procedure that allow to deposit TiO2 layers of controlled thicknesses and different morphology (rugged or compact). The composite containing the rugged TiO2 layer was shown to possess significantly higher activity in MB degradation and in photoassisted H2O oxidation under 400 nm. This improved photoactivity was attributed to a higher porosity and better accessibility of ZnO/TiO2 interface region through the rugged TiO2 layer by the reagents. The effort was also made to enhance the visible light activity of the composites. To this aim the composites consisting of ITO-supported ZnO nanorods covered with nitrogen-doped titanium dioxide and decorated with Au nanoparticles. It was found that even a low Au loading (0.37% at.) resulted in 60% enhancement of photocatalytic decolorization of MB under visible light with respect to the Au-free sample owing to plasmonic effects. A simultaneous N-doping and Au decoration allowed also to multiply by three the photocurrent in photoassited water oxidation
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Wei-HungChen and 陳韋宏. "Thermoelectric properties of homologous In2O3(ZnO)n and ZnO nanowires." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/48103038620508619239.
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碩士<br>國立成功大學<br>材料科學及工程學系碩博士班<br>101<br>In this experiment,ZnO nanowires are transformed into homologous
In2O3(ZnO)n nanowires by solid state reactions. In2O3(ZnO)n nanowires with different InO2- layer densities and surface morphology can be obtained by controlling the thickness of the indium coating by thermal evaporation. Scanning electron microscopy and high angle annular dark field images are employed for analyzing lattice stacking and diffusion mechanism.Subsequently,we use e-beam lithography to take measure- ements including several nanodevices based on single In2O3(ZnO)n and ZnO nanowires, four-point resistance,metal oxide semiconductor field effect transistor, Seebeck coefficient, thermal conductivity.
By comparing the structural differences between In2O3(ZnO)n and ZnO nanowires, we aim to study how InO2- layers change conductivity, carrier mobility, carrier concentration, Seebeck coefficient, thermal conductivity, figure of merit (ZT).The results show that, compared with a typical undoped ZnO nanowire, the as synthesized In2O3(ZnO)n nanowires possess more superior physical properties on Seebeck coefficient, thermal conductivity, whereas the corresponding electrical conductivity along with the power factor degrade. As a result,by combining all the properties, ZT is indeed increased,for the homologous nanowires.
From our experiments,the electrical conductivity of the In2O3(ZnO)n nanowires increases significantly with temperature. In literature, thermal conductivity has been reported to remain constant and Seebeck coefficient increases slightly with the increasing of temperature. Thus, we predict that ZT will increase significantly at high temperatures.
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jiang, jhong-ying, and 江忠穎. "The study of p-NiO/MgZnO-ZnO quantum well/n-ZnO photodetectors." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/3wn4jh.
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碩士<br>國立嘉義大學<br>電子物理學系光電暨固態電子研究所<br>106<br>In this thesis, the p-i-n diodes were fabricated by depositing p-NiO/MgZnO-ZnO quantum well (QW)/n-ZnO structure on ITO/glass substrate using magnetron sputtering system. First, the n-ZnO was deposited on ITO/glass substrate, then the MgZnO/ZnO QW was grown on ZnO surface with various MgZnO barrier layer thickness (10, 25, 40, and 60 nm) and ZnO well thickness of 4 nm. Next, p-NiO and electrodes were coated to fabricate the p-i-n diodes. Effects of various barrier layer thickness on the diodes were studied.
The p-n diodes without QW structure (i.e., p-NiO/n-ZnO) exhibited rectifier characteristic, but the rectifier characteristic was improved after adding MgZnO/ZnO QW. As compared with the diodes without QW, the rectification ratio was greatly enhanced from 14.9 to 95.7 at ±2.5 V bias-voltage. As for photoresponse, both the visible- and ultraviolet-photoresponse decreased with barrier layer thickness. The largest 280/500 nm rejection ratio was observed in the p-i-n diodes with QW structure. The 280/500 nm rejection ratio was enhanced from 159 for the diodes without QW to 3030 for the diodes with QW and 25-nm barrier layer thickness by a magnitude of 19 at 1-V reverse-bias voltage, indicating the diodes with QW and 25-nm barrier layer thickness presented the largest noise-rejection ability.
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Chan, Hui-Tzu, and 詹惠慈. "Study of ohmic contact to n-type ZnO." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/yp47hz.
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碩士<br>中原大學<br>電子工程研究所<br>98<br>Zinc oxide (ZnO), a wide-gap (3.37eV at room temperature) semiconductor with a high exciton binding energy (60 meV), has emerged as a candidate for use in short-wavelength optoelectronic devices such as ultraviolet (UV) lasers and light-emitting diodes (LEDs). Due to its high thermal and chemical stability in an air ambient, high transmittance (&gt;90%), good electrical conductivity and high optical transparency, ZnO has also attracted more attention in the applications of display devices, solar cells, UV LEDs, and electronic transducers.
In this thesis, ZnO thin films were grown on silicon substrates by the atmospheric pressure chemical-vapor deposition (AP-MOCVD). On these ZnO films metal systems were deposited by E-Gun to form ohmic contact. Ti/Ag or Ti//Pd/Ag metal system was deposited on ZnO:Ga to form ohmic contact. The annealing temperature, annealing time and metal structure thickness were optimized to achieve low specific contact resistance.
In summary, a low specific contact resistance of 2.92×10-5Ω-cm2 can be obtained for the ZnO:Ga film with carrier concentration~6.48×1019cm-3 by forming Ti/Ag(10nm/300nm) ohmic contact to it under annealing conditions: 200℃, 60 sec, and in N2 ambient. A low specific contact resistance of 2.70×10-5Ω-cm2 can be obtained for the ZnO:Ga film with carrier concentration~2.14×1019cm-3 by forming Ti/Pd/Ag(10nm/10nm/300nm) ohmic contact to it under annealing conditions: 150℃, 60 sec, and in N2 ambient. A low specific contact resistance of 4.14×10-4Ω-cm2 can be obtained for the ZnO:Ga film with carrier concentration~2.53×1018cm-3 by forming Ti/Pd/Ag(10nm/10nm/300nm) ohmic contact to it under annealing conditions: 250℃, 60 sec, and in N2 ambient.
It is noteworthy that even the ZnO:Ga film with a lower carrier concentration ~2.14×1019cm-3 about half an order lower than that (~6.48×1019cm-3) where Ti/Ag contact is formed, a similar specific contact resistance has been achieved by forming Ti/Pd/Ag contact to the former. This is suggested to be due to that Pd can prevent Ti and Ag from interdiffusion.
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Hu, Chen-Min, and 胡茜閔. "Study of Ohmic Contacts to n-type ZnO." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/49744306043498052806.
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碩士<br>正修科技大學<br>電子工程研究所<br>96<br>In this study, ohmic contacts of metal Al deposited on n-type ZnO:Al (2.0×1018 cm-3) were studied by current–voltage (I-V) and transmission-line-method (TLM) measurements. It is shown that Al contacts as-deposited and annealed at 100°C for 1 min under a vacuum ambient show ohmic contact with good characteristics. The specific contact resistivity of as-deposited Al is 5.02 ×10-4 Ωcm2. The best ohmic contact to n-type ZnO:Al was obtained using a Al contact that was annealed at 100°C for 1 min under a Vacuum ambient, showing a specific contact resistance Rc of 4.05×10−4 Ωcm2. The results of Auger electron spectroscopy (AES) measurements indicate that an interfacial reaction between Al and ZnO results in an increasing of doping concentration in the region of the interface between Al and ZnO, which results in a low specific contact resistivity.
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Lai, Jian-Hung, and 賴建宏. "Schottky contacts on n-type ZnO thin films." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/92917623040509478381.
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碩士<br>國立臺灣大學<br>物理研究所<br>96<br>The formation and properties of Schottky contacts to ZnO thin films have been investigated. Since ZnO possesses superior properties in many aspects, Schottky contact are needed to realize some ZnO-based devices. In this work, ZnO thin films were grown by fast pulsed laser deposition. Au Schottky contacts were deposited by radio frequency magnetron sputtering but their current-voltage relations show ohmic characteristics or Schottky behavior with a high leakage current. In order to improve the Schottky behavior, the hydrogen peroxide treatment was used on the ZnO thin films before the deposition of Au. After the treatment, the sample possessed good Schottky contacts and up to four orders of magnitude in rectification of the current was obtained for the bias between -2V and +2 V. This method was applied to ceramic materials and the conversion from ohmic to Schottky behavior was also found. Finally, the effect of hydrogen peroxide treatment on the ZnO surface was studied using Van der Pauw measurement, Kelvin probe force microscopy, atomic force microscopy, and photoluminescence.
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Lai, Jian-Hung. "Schottky contacts on n-type ZnO thin films." 2008. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2606200813372700.
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Chan, Yi-ming, and 詹益明. "Study of p-Cu2O / n-ZnO Heterojunction Solar Cells." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/24607711247921433921.
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碩士<br>國立臺灣科技大學<br>工程技術研究所<br>98<br>This study described p-Cu2O/n-ZnO and p-Cu2O/n-AZO heterojuction solar cells that were fabricated by two kinds of methods. Fabrication of p-Cu2O thin film has been conducted by RF O2 plasma oxidizing and microwave plasma oxidizing, respectively. On the other hand, fabrication of n-ZnO and n-AZO thin films have been achieved by sputter deposition.
For the analyses of thin films, elements and surface structure of p-Cu2O thin films was characterized by SEM and XRD measurements. Composition and surface structure of n-ZnO and n-AZO thin films and surface structure were analyzed by SEM and XRD. Mobility, carrier concentrations and optoical properties of ZnO and AZO films were measured by UV and Hall measurement.
For the analysis of solar cells, ITO thin film and metal electrode were added by sputter and screen printing for I-V measurement. Performance of p-Cu2O/n-ZnO and p-Cu2O/n-AZO heterojuction solar cells were compared. The best results were Voc = 0.3 V、Isc = 2.48 mA、FF = 0.34 and η = 0.301% for the solar cell with 938 nm p-Cu2O by microwave plasma and 400 nm n-AZO.
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Liu, Chi-Pin, and 劉啟賓. "Fabrication of ZnO p-n diode by thermal evaporation." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/71157971032391742251.
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碩士<br>國立高雄大學<br>電機工程學系碩士班<br>99<br>The p-type nitrogen-doped zinc oxide thin films were prepared by the thermal oxidation of thermal evaporated zinc nitride powder. Combing with the n-type zinc oxide prepared by sputtering or spraying, the zinc oxide p-n diode can be fabricated. The stacked structures with different thermal treatment temperature were accomplished. The current-voltage and spectral responsivity behaviors were investigated. The diode with spraying n-type zinc oxide followed by 550℃ thermal treatment shows the sharp cutoff wavelength in the spectral responsivity and less reverse biased dark current, but the diode by 450℃ thermal treatment shows the highest rejection ratio around three orders of magnitude.
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YeeLim, Sin, and 林芯儀. "Synthesis and Opto-electrical properties of Indium doped ZnO nanowires and In2O3(ZnO)n superlattice structure." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/28009217313139602781.
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碩士<br>國立成功大學<br>材料科學及工程學系碩博士班<br>101<br>In this work, the effect of Indium (In) concentration on the structure, microstructure, luminescence and electrical properties of ZnO nanowires have been investigated. In doped ZnO nanowires are grown on Si substrate by Chemical Vapor Deposition method, at a relatively low temperature (550 °C). The average diameter and length of these nanowires vary from 70-311 nm and 10-15 μm, respectively. These nanowires are single crystals growing along the [0001] direction. The maximum solubility of In in ZnO is estimated to be 3.47 at.%. Photoluminescence (PL) spectra reveal both ultraviolet (UV) and visible luminescence. Careful observations PL spectra indicate a red shift in the UV emission and the enhancement in the intensity of the green emission with increasing In content. Single nanowire Field Effect Transistor devices are fabricated to determine the carrier concentration, mobility and resistivity of the individual nanowires.
In addition, homologous In2O3(ZnO)n superlattice nanowires have been successfully synthesized on Si substrate by evaporating ZnO and In2O3 mixed powders, using Au as a catalyst. There are two types of superlattice nanowires in the product, namely, longitudinal and transverse superlattice structure. Longitudinal superlattice nanowires have bumpy surface with the length about 1-5 μm and diameter around 45-100 nm whereas transverse superlattice nanowires have a smooth surface with the length about 10-15 μm and diameter around 20-50 nm. It is found that they consist of In-O octahedral layers, as inversion domain boundaries, and In-doped ZnO layers (In/Zn-O layers) stacked alternately perpendicular to the c axis. Besides, zigzag-modulated structures are also formed within the In/Zn-O layers as the secondary polarity inversion boundaries. The resistivity of the longitudinal superlattice nanowires is found to be lower than that of the transverse superlattice nanowires. Cathodoluminescence of the longitudinal and transverse superlattice nanowires show a dominant emission at 3.25 eV with different defect bands located in the range of 450 nm to 750 nm, indicating that different defects are formed in these structures.
Lastly, the photodetectors of the In-doped ZnO nanowires and In2O3(ZnO)n superlattice nanowires with photoconductive gain, G ~103-104 have been fabricated and characterized, under a illumination of 325 nm UV light. The UV photosensitivity (photo-to-dark current ratio) of the In doped ZnO nanowires (742%) is about 5 times higher than the In2O3(ZnO)n superlattice nanowires (160%). Besides, the photoresponse measurement shows an exponential growth and bi-exponential decay of the photocurrent from both the In doped ZnO nanowires and the In2O3(ZnO)n superlattice nanowires. However, due to the presence of more oxygen vacancies on the as-grown In doped ZnO nanowires, they show a faster photoresponse than that of the In2O3(ZnO)n superlattice nanowires. The reproducible photocurrent response and high photosensitivity of the fabricated In-doped ZnO nanowires photodetectors suggest that the devices have potential applications in UV photodetection.
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Wang, JUN JIE, and 王俊杰. "Study of N-type and P-type ZnO thin films." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/79514503364411902943.
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碩士<br>大葉大學<br>電機工程學系<br>102<br>We have fabricated zinc oxide thin film on silicon substrate by the Radio Frequency(RF) magnetron sputtering. Preparation of the zinc oxide thin film (ZnO) ,in the environment of plasma argon pressure
4.0×10-2 Torr(mTorr), the sputtering power of samples is 100 watt for 2 hour , and controlled the percentage of nitrogen (0%, 10%, 20%, 37.5%). ZnO thin film can be measured by X-ray diffraction(XRD), Scanning Electron Microscope (SEM) and Atomic Force Microscope(AFM) . Hall effect measures are measured in the different parameters including the carrier concentration, carrier mobility, and resistivity. The lowest resistivity which can be used as P-type ZnO thin film. PN diodes can be fabricated in N-type and P-type ZnO thin film. We use semiconductor electrical measurement (HP4155A) to measure the rectification characteristics.
The present results are the sample of nitrogen-doped 15 mTorr(37.5%). XRD results can measure in the obvious ZnO peak . AFM measurements show that the largest particle size, SEM results can be seen most clearly in the hexagonal wurtzite structure of ZnO thin films. Hall effect measurement can be found in the lowest resistivity which can be used as P-type ZnO thin film. Using the instrument of the PN diodes measurement to observe the rectification characteristics, which show that PN diode reverse bias and forward bias asymmetry.
Key Words: X-ray diffraction, Hall effect measurement, Scanning Electron Microscope, Atomic Force Microscope
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Lee, Tsung-Han, and 李宗翰. "Research of the Co3O4/ZnO p-n Type Piezoelectric Transducers." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/66234918700138194613.
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碩士<br>國立臺灣大學<br>應用力學研究所<br>102<br>Enabling technologies for wireless sensor networks have gained considerable attention in research communities over the past few years. With the development of the low powered small wireless electronic devices, it is highly desirable, even necessary in certain situations, for wireless sensor nodes to be self-powered.
This research develops a ZnO piezoelectric transducers that can be operated in low frequency. A ZnO films and Co3O4 films were well-deposited on flexible titanium (Ti) foil of 80 μm and ZnO/Ti structure. The ZnO deposited on Ti foil performed a best piezoelectric coefficient at the specific sputtering parameters, and showed a good textured structure via XRD, SEM, EDS and AFM measurements.
However, we utilize n-type zinc oxide (ZnO) and p-type cobalt oxide (Co3O4) to develop a p-n type piezoelectric transducers. The Co3O4-ZnO interface forms a p-n junction. When two capacitors are connected in series, their overall capacitance is less than that of either. It can reduce the impedance to enhance the output voltage. Also, it can increase the difference in Fermi levels between two electrodes. This structure enhances the output power efficiently. From the experiment results, the output voltage and power of the p-n type piezoelectric transducer is around 1.5 times and 10.6 times of ZnO piezoelectric transducers at the same strain respectively.
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Huang, Shin-hao, and 黃信豪. "The Study of ZnO P-N Homojunction by Sputtering Method." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/29032184523253158558.
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碩士<br>國立高雄第一科技大學<br>光電工程研究所<br>101<br>Indium tin oxide (ITO) and zinc oxide (ZnO) are transparent conductive material that have been used on solar cells and the flat display applications as the electrode. In this study, indium tin oxide (ITO) as the base electrode layer that has low surface electrical resistance and high visible light transmittance, and zinc oxide (ZnO) and Nitrogen-doped sputtered ZnO as the n-type and p-type semiconductor layers, respectively, are stacked to form a p-n junction device. Due to the high band gap ranged from about 3.2eV ~ 4.2 eV, both ITO and ZnO are transparent in the visible range (400nm ~ 700nm) and shown absorption below 400nm in the UV light band.
At first, we are sputtering indium tin oxide (ITO) deposited on a glass substrate, we are annealing adjust temperature and holding the temperature at sputtering method that can measurement the surface impedance at 20Ω/cm2 and control the band gap range of 3.7eV to 3.9eV.
Next, through change of Ar:N2 mixing ratio, the nitrogen-doped p-type zinc oxide can be obtained by sputtering deposition. Finally, a ITO / n-type ZnO / p-type ZnO / Ag structure is fabricated and measured by IV & CV. Besides, sheet resistance, surface morphology and optical property are characterized by four-point probe, SEM and photoelectron spectroscopy analyzer, respectively.
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Huang, Guo-Sin, and 黃國欣. "All-ZnO P-N Diodes Fabricated by Variations of Orientation." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/16587456722281434213.
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碩士<br>國立中山大學<br>物理學系研究所<br>100<br>This thesis investigates the effects of varying the crystallographic orientations of epitaxial ZnO thin films to produce functional ZnO P-N diodes. First, with the atomic layer deposition (ALD), a p-type m-oriented ZnO epitaxial layer is deposited onto an also m-oriented Al2O3 substrate. Then an n-type ZnO layer, mostly textured along the c-axis, is grown atop to form a P-N diode by RF sputtering method.
The Hall Effect of the m-ZnO thin film is measured separately at various temperatures and magnetic fields in Quantum Design’s Physical Property Measurement System (PPMS) to determine the nature of the charge carriers. The m-oriented ZnO films are found to be p-type semiconductors, with carrier concentration approximately ~ 1021 1/cm3, which falls in the category of highly-doped degenerate semiconductor. In order to further prove that these films are indeed p-type, naturally n-type c-textured ZnO films are put on the m-films at room temperature by magnetron sputtering to see if the current-voltage (I-V) curves do follow the P-N junction characteristics. In optimizing the c-ZnO film quality and reducing the effects of the junction defects, the gas-mixture ratio between argon and oxygen was varied to compare for the changes in the performance of the resulted materials and devices.
X-ray diffraction was used to characterize the crystallographic orientations and the general qualities of the samples by 2θ-ω scan, rocking scan, φ-scan and pole figure measurement. Understanding of the P-N diode is acquired through the analysis of the leakage current and the quantum tunneling phenomena as manifested in the I-V characteristics.
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Chih-HuangPan and 潘誌煌. "Fabrication of p-Cu2O/n-ZnO Heterojunction Nanorod by Electrodeposition." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/95454024758472639256.
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碩士<br>國立成功大學<br>材料科學及工程學系碩博士班<br>100<br>In this research, we used two-step electrochemical deposition to synthesize the Cu2O/ZnO core-shell heterojunction nanorod in the porous alumina membrane. We used the porous alumina membrane with pore sizes in the range from 100 to 140 nm as the template in order to avoid the hydrogen accumulated, which will prejudiced the electrochemical deposition. The first deposition was controlled the current density of deposition to deposit the copper metal nanowire, and when the deposition conditions of the current density was 5mA/cm2, the copper were deposited in the porous alumina membrane which determined from X-ray diffraction (XRD) patterns. By the TEM analysis, we found the crystalline of copper will improved with increasing the current density of deposition. When the current density was increased to 20mA/cm2, the single crystal copper nanowires were synthesized in the porous alumina membrane.
Before the second deposition, we used the NaOH to remove the alumina template, in order to increase the contact area of the electrode and electrolyte. The second deposition used the copper nanowire as the electrode to deposit the zinc, the formation of Cu / Zn heterojunction nanowires.
Finally, we annealed the Cu/Zn heterojunction nanowires at 400 oC to syn-thesize the Cu2O/ZnO heterojunction nanowires.The average length and average of the Cu2O-ZnO heterojunction nanowire were 7 um and 140 nm.
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LIU, CHENG-YOU, and 劉承祐. "Photocatalytic Study of ZnO(:N)/MoO3(:In) Heterostructure Thin Film." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/q3k3pt.
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碩士<br>國立高雄大學<br>電機工程學系碩博士班<br>107<br>In this thesis, ZnO/ZnO:N/MoO3 thin films were fabricated on a ruthenium substrate by spray pyrolysis. The effects of different N concentrations were discussed in terms of structure, including surface morphology, structural thin film phase, photoexcitation spectroscopy and photocatalysis. Characteristics and so on. At the appropriate N concentration doping, there is an optimum photocatalytic ability. Next, ZnO:N was replaced by MoO3:In to investigate the photocatalytic properties of different concentrations of In. Finally, the best two photocatalytic samples were used to form a four-layer structure of ZnO/ZnO:N/MoO3:In/MoO3, and its photocatalytic ability was discussed.
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LIN, YU-YOU, and 林昱佑. "Study on characteristics of Sb/N doped ZnO Thin Films." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/v6u664.
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碩士<br>國立臺北科技大學<br>光電工程系<br>107<br>A. Krtschil proposed co-doping theory, which states that dual acceptor co-doping will effectively increase carrier concentration. In this study, the effect of a carrier concentration of monodoped ZnO on a carrier concentration of (Sb, N) co-doped ZnO was investigated. The structural properties of ZnO thin film were characterized by X-ray diffraction (XRD), and the electric properties of ZnO thin film were analyzed using the Hall– effect measurement.
The experiment was divided into four steps. The first step was to incorporate nitrogen into the ZnO thin films. By adjusting the ratio of zinc to nitrogen in the solution, five different carrier concentrations were obtained. The second step was to incorporate antimony into the ZnO thin films. By adjusting the percentage of antimony atoms in the solution, three different carrier concentrations were obtained. The third step was to incorporate antimony of 2 at% into the nitrogen doped ZnO thin films of five different carrier concentrations. The final step was to keep the zinc to nitrogen concentration at a fixed ratio of 1:3 and incorporate it into three different atomic percentages.
Adjusting the ratio of zinc to nitrogen in solution ,the nitrogen-doped ZnO can increase the carrier concentration from 1.73ⅹ1016 (cm-3) to 4.22ⅹ1017 (cm-3) .Fixed antimony doping concentration , adjusting the ratio of zinc to nitrogen in solution. The carrier concentration of Sb/N doped ZnO thin films can increase to 6.53ⅹ1017(cm-3) from7.16ⅹ1017(cm-3). The Sb/N co-doped ZnO films have zinc-to-nitrogen ratios of 1:2 and 1:3 and 2at% antimony doping concentration is. The carrier concentration of Sb-N co-doped ZnO is higer than the combined concentration of N and Sb single doped ZnO. Solubility could be effectively improved when codoped with antimony and nitrogen was at specific ratios.
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Tan, Qiao-Meng, and 陳俏蒙. "Resistance Switching in ZnO-Based Memristors with a p-n Junction." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/d3gz7g.
Full textAbstract:
碩士<br>國立東華大學<br>物理學系<br>105<br>Resistance switching in ZnO-based memristive devices with a p-n junction has been investigated. Sputtering was performed to prepare devices with layered structures as Ti/ZnO/p+-Si. Programming strategies were developed in terms of using different operation modes, including voltage sweep mode, current sweep mode, and single-pulse mode. The single-pulse mode was found to suppress the multiplicity of the readout resistance levels as compared with the voltage/voltage sweep modes. Furthermore, current compliance was found to significantly affect the device stability during repeated switching operations. Conduction processes leading to the resistive switching were examined for the low-resistance and high-resistance states, conforming the mechanisms dominated by space charge limited current (SCLC) and Poole-Frenkel (PL) trap-associated processes respectively. Instability and device failures were attributed to structural imperfections resulting from preparations.
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Wang, Chien-Shin, and 王建欣. "Fabrication and Characterization of ZnO Thin Film P-N Junction Devices." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/83190873552438664225.
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碩士<br>大葉大學<br>電機工程學系<br>102<br>In this study, the ZnO p-n junctions were fabricated on Si (0 0 1) substrates by the rf magnetron sputtering system to investigate the electrical and optical properties. In the first phase, ZnO thin films were fabricated on Si (0 0 1) substrates with various nitrogen volume percentage at different temperature (room temperature, 200 C, 300 C, and 400 C), where nitrogen was introduced to the growth chamber as the p-type dopant source. During the growth of the films, the reactive gas nitrogen was firstly introduced to the chamber with different pressure, and then the working gas argon flew in to keep the total pressure at 40 mTorr. The X-ray diffraction data showed the [0 0 1] direction of the ZnO:N films is perpendicular to the substrate surface. To characterize the deposited thin films, resistivity, carrier concentration, and carrier mobility were measured by the Hall measurement system. The ZnO:N thins films grown at high-temperature show a positive sign of the Hall coefficient confirmed that the p-type conductivity.
In the second phase, a photoresist was coating on the previously prepared p-type ZnO:N films surface. Next, an exposure and development process was performed to define the passivation region on the photoresist layer. Then, the resist pattern was transferred into ZnO:N via wet etching. The second ZnO layer was patterned by lift-off method. A sacrificial photoresist layer was first deposited on the patterned p-type ZnO, then the inverse pattern was created via exposure and development. After the n-type ZnO thin film was fabricated over the whole area, the sacrificial was washed away by acetone to reveal the desired pattern. The I-V characteristics, hall coefficient, and photoconductivity were measured to explore the properties of the ZnO devices.
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Chang, Jun-po, and 張潤博. "The fabrication of an interdigital p-Cu2O/n-ZNO heterojunction diode." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/82153405070186624681.
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碩士<br>國立高雄第一科技大學<br>光電工程研究所<br>101<br>This study described the fabrication of an interdigital p-Cu2O/n-ZnO
heterojunction diode. First, ITO films were fabricated of by RF magnetron
sputtering and post-preparation annealing at high-temperature in order to improve the
conductivity of ITO films. Secondary, Cu2O films were grown by RF magnetron
sputtering, in which Cu was used as the sputtering target. The RF power and the O2
flow rate was changed in order to obtain a cuprous oxide film with different
characteristics. Finally, ZnO films were grown by RF magnetron sputtering, in
which ZnO was used as the sputtering target. The RF power was changed in order to
obtain a ZnO film with different characteristics.
Crystallinity and surface morphology of ITO、 Cu2O、ZnO thin film were
characterized by XRD and SEM measurements. Conductivity of post-preparation
annealing ITO thin films at different annealing temperatures was measured by
multimeter. The junction properties of Interdigital p-Cu2O/n-ZnO heterojunction
diode were investigated by current-voltage (I-V) and capacitance-voltage(C-V)
measurements.
The annealing temperature was maintained at 500℃ for 30 minutes that provided
an improved crystallinity and conductivity of ITO thin film. The crystallinity and
morphology of Cu2O film were close related to the RF sputtering power. At RF
sputtering power of 60W and oxygen flow rate of 1 sccm, the preferred orientation of
(111) Cu2O film can be obtained. We found an improvement in the ZnO film’s
crystallinity with the increase of the RF power.
The Cu2O/ZnO heterojunction with film thickness of about 400nm showed
higher reverse saturation current in I-V measurement, compared to the one with film
thickness of 600nm.
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Tu, Tsung-Hsien, and 凃宗賢. "A study on the Ag/n-ZnO thin film Schottky diode." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/91343592370066964362.
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碩士<br>崑山科技大學<br>光電工程研究所<br>100<br>The preparation of sol-gelprocessed zinc oxide (ZnO) thin film and ZnO based Schottky were proposed in the thesis.The ZnO thin film was deposited on Si substrate and annealed by rapid thermal annealing at 800℃ for 45 sec.The electrodes of the Schottky diode was deposited silver by thermal evaporation and then were annealed by RTA at 200 and 350℃,
respectively.The Schottky diode shows a barrier height of 0.84 eV with an ideality factor of 1.74 and a reverse leakage current of 0.12 mA after was annealed at 350℃. In addition,the Norde model and Cheung''s equation,were also used to discuss the barrier height and series resistance effects.For the temperature dependent current-voltage characteristics, the Schottky diode shows a increase of barrier height and a decrease of ideality factor as the measured temperature increased. The barrier inhomogeneous effect it was also discussed through Gauss distribution
model in the temperature dependent effects.
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Chung, Ping-Ying, and 鍾秉穎. "Influence of Phosphorus doped ZnO: N on P-type Zinc Oxide." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/c8fc6b.
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碩士<br>大同大學<br>電機工程學系(所)<br>107<br>The main purpose of the research is using phosphoric acid to dope P-type ZnO:N semiconductor thin films. We use a DC magnetron sputtering system to deposit zinc nitride precursors, and use phosphoric acid to add hydrogen peroxide to form a phosphorus-doped zinc oxide nitrogen film. In this paper, the structure of zinc nitride film is affected by environmental factors under different phosphoric acid concentrations and different micro-oxidation time conditions, and using XRD and Raman to analyze the oxygen and phosphorus content in the film. It was found that phosphorus did enter the zinc nitride film, and the doped phosphoric acid hydrogen peroxide aqueous solution can obtain P-type conductive zinc oxide at an appropriate concentration, and make an oxy zinc thin film diode. In the experimental analysis, a new concept of forming P-type zinc oxide by micro-phosphorization of doped phosphorus by adding phosphoric acid has been proposed.
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Kumar, Sandeep. "Fabrication and Characterization of ZnO Thin Film Based p-n Junction." Thesis, 2015. http://ethesis.nitrkl.ac.in/7693/1/2015_Fabrication_Kumar.pdf.
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Zinc Oxide (ZnO) thin films have drawn considerable interest due to its excellent material properties such as wide and direct band gap, high electron mobility and large exciton binding energy. In order to realise the applications of these devices, fabrication of high quality p-type ZnO thin films are very essential. In this work p-ZnO/n-ZnO and p-ZnO/n-Si type of junctions were realised by depositing the (Al, N) doped p-ZnO films on glass and silicon substrate using low cost sol gel as well as dip coating techniques. The characterization of deposited thin films was carried out by XRD, UV visible spectroscopy, and I-V measurements. For qualitative confirmation for p-type conduction of deposited ZnO thin film hot probe method is utilised. A comparative study of the different p-n junctions was done, where homo-junction between p-ZnO (dip coated) and n-ZnO(sputtered) shows a better diode characterises.
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Haung, Ru-Ting, and 黃如廷. "Energy Efficient p-GaN/n-ZnO Light-Emitting Diodes Based On ZnO/graphene Composite Nanorods Prepared By Hydrothermal Method." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/22222286157729404233.
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碩士<br>國立臺灣海洋大學<br>光電科學研究所<br>103<br>Enhanced electroluminesce (EL) of GaN/ZnO composite nanorods light-emitting diodes (LEDs) based on ZnO/graphene composites utilizing the excellent properties of graphene, such as high electrical conductivity and high light transparency were realized. The LEDs using ZnO/graphene composite nanorods with proper concentrations of graphene showed enhanced EL and photoluminecence (PL) with respect to that of LEDs with only pure ZnO nanorods. The enhanced light output power of energy efficient p-GaN/n-ZnO composite nanorods LEDs reported here can be possibly attributed to the important role of graphene flakes in ZnO/graphene composite nanorods acting as a conducting network in the ZnO active matrix that leads to the improved electrical conductivity and the surface plasmon (SP) enhanced light emission.
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Hung, Sung-Wei, and 洪松慰. "Syntheses and Characterization of Multi-functional N-doped Nano-ZnO Visible Light Photocatalyst and ZnO-Ag Nano-composite Particles." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/nwa54g.
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碩士<br>國立臺北科技大學<br>材料科學與工程研究所<br>95<br>In this study, N-doped ZnO nanoparticles with rod-like and tetrapod-like morphologies were synthesized on a mass scale using the DC thermal plasma approach. The N-doped ZnO nanoparticle has a strong absorption below 420 nm and significant absorption in the visible range from 450 to 650 nm. Ag nano-colloids were prepared by chemical reduction with the presence of citrate ion, which modified the surface properties of Ag nanoparticle. After complete mixing, the Ag nanoparticles can adhere to the surface of N-doped ZnO nanoparticle to form ZnO-Ag nano-composite particles (NCPs) due to the attraction between the positively charged ZnO surface and the negatively charged Ag surface. The experimental results indicate that ZnO-Ag composite has semicoherent interface boundary. The amount of Ag nanoparticles absorbed on the surface of N-doped ZnO nanoparticle, is related to the surface charge density of the N-doped ZnO nanoparticle. Citrate ions play the role of selective absorption site on N-doped ZnO nanoparticle surface.
Although decomposition efficiency of methylene blue (MB) under UV irradiation does not appear to differ from each other, ZnO with a higher N-doped concentration has better decomposition performance under visible light illumination. This is due to that oxygen vacancies prolong the recombination of electron and hole. The decomposition performance of methylene blue (MB) by ZnO-Ag NCPs significantly exceeded that by N-doped ZnO nanoparticles under UV irradiation, because the Ag nanoparticles act as electron traps, which enhances electron-hole separation. However, there is almost no difference in methylene blue (MB) decomposition efficiency between the ZnO-Ag NCPs and the N-doped ZnO nanoparticles under visible light. The Ag nanoparticles behave incompletely equivalent under UV irradiation and visible light due to the surface plasmon resonance absorption of Ag nanoparticles, which is only induced by visible light. Ag nanoparticles can decompose methylene blue (MB) during illumination with visible light.
Increasing the N-dopant concentration of ZnO nanoparticles improves anti-bacterial performance because oxygen vacancies prolong the recombination of electron and hole. The anti-bacterial performance of N-doped ZnO nanoparticles under visible light is better than that of commercial ZnO nanoparticles. The N-doped ZnO nanoparticles exhibit additionally the intrinsic photocatalytic activity for anti-bacterial performance. N-doped ZnO nanoparticles modified with a coating of Ag nano-dots on their surface perform as well as N-doped ZnO nanoparticles do, during 3 hours of illumination with visible light with a wavelength of 543 nm. However, the performance of ZnO-Ag NCPs is improved by approximately two orders of magnitude in the dark. Mildew resistance tests indicate N-doped ZnO nanoparticles has excellent performance of zero-level.
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Yung-ChunTu and 凃詠俊. "Fabrication of UV detectors based on laterally-oriented ZnO nanowires and n-ZnO/p-SnO (or p-CuO) nano heterojunctions." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/63747259779900439596.
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Zhuang, Jun-Hui, and 莊俊輝. "The Study of P-Si/N-ZnO Hetero-Junction as a Photo-Detector with ZnO Film Prepared by Spray Pyrolysis." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/06794084512447008912.
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碩士<br>吳鳳科技大學<br>光機電暨材料研究所<br>102<br>In this work, we developed spray pyrolysis equipment for deposition of ZnO thin films and prepared p-Si/n-ZnO hetero-junction structure serving a photodetector. The effect of process parameters on photoelectric properties of prepared n-ZnO films was made by varying solution concentration, growth temperature, time, and solution preparation-days.
The optimal n-ZnO film properties with resistivity of 2.84*10+01Ωcm and transmittance of about 80% were achieved with the process parameters of Zinc acetate of 2g, growth temperature of 400℃, growth time of 2 hr., and solution prepared after 15 days. The proposed p-Si/n-ZnO device structure shows a significant increase in reverse current density under UV (365 nm in wavelength) illumination. A distinct increase in the photo induced current density of about 6.5 times under UV light irradiation (on, off continuous switching) and 5V reverse bias was obtained. Experimental results show that the use of the n-ZnO film prepared by spray pyrolysis method reveals a relatively better photoelectric response as compared to that of the p-Si/n-ZnO device with a sputtered n-ZnO film.
The spray pyrolysis process is cost effect, easy to dope, and can be conducted for large-area coating. The device developed in this research would have a great potential for application development in serving as UV detection, the sensors and other optoelectronic components.
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Kuo, Li-Chun, and 郭俐君. "Properties of N-doped ZnO Films Deposited Using Plasma Enhanced AtomicLayer Deposition." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/49nhgm.
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碩士<br>中原大學<br>電子工程研究所<br>99<br>Radio frequency plasma enhanced atomic layer deposition (RF-PEALD) technique was used to deposit nitrogen-doped (N-doped) p-type ZnO thin films on sapphire substrate at 75 - 250oC with an RF power of plasma source 0 - 200 W and NH3 flow rate of 5 – 50 sccm. Ammonia (NH3) gas, decomposed by the plasma to form N, NH and NH2, was used as the source of nitrogen and the flow rate of it was varied. The N-doped ZnO was deposited on sapphire substrate, and the thickness of 110 nm. Post-annealing treatment was conducted to remove the hydrogen ions in the as-grown films at 800oC to 900oC by a rapid thermal annealing (RTA) system.
N-doped ZnO films were characterized by Hall measurements, X-ray diffraction (XRD), low temperature photoluminescence (LTPL) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Hall measurements showed the highest hole concentration of 4.041017 cm-3, the lowest resistivity of 52.10 -cm, and the hole mobility of 0.55 cm2/V-s for N-doped ZnO, which was fabricated at 100oC substrate temperature 、with RF power of 100W and NH3 flow rate of 10sccm. Besides, the crystallographic structures and bonding configurations obtained from the XRD results demonstrated the formation of No acceptors by substituting N atom for O sublattice or N2 for O atom. The LTPL spectra for N-doped p-type ZnO films exhibited the emissions ascribed to the neutral donor bound excitons (DoX) at 3.361 eV, free electrons to acceptor (FA) transition at 3.311 eV, and the donor-acceptor pair (DAP) recombination at 3.255 eV with a weaker peak at 3.180 eV assigned to the longitudinal optical (LO) phonons. The appearance of both FA and DAP transitions related emissions are suggested to be associated with the replacement of N atom for O atom (No) in ZnO. XPS results indicated that a part of N substrate O atom to form the accepter-like defects. The binding energy of No could be established at 397.5 eV.
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Chung, Ting-Tse, and 鍾定澤. "Characterization of ZnO:Sb/ZnO p-n junctions grown by pulsed-laser deposition." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/rwa353.
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碩士<br>國立臺北科技大學<br>光電工程系研究所<br>100<br>In this study, Sb-doped ZnO films are used for the p-type sides and intrinsic ZnO films for the n-type sides of p-n junctions grown by pulsed-laser deposition. ZnO films have been deposited on (002) sapphire substrates in an ambient gas of oxygen to reduce oxygen vacancies. P-type ZnO:Sb films have been cooled in nitrogen ambient to raise the hole concentration.
We found another procedure which can removal the schottky effect in p-type ZnO:Sb films during the current-to-voltage (I-V) measurement. And distinct rectifying I-V characteristics are observed for junctions between ZnO and p-type ZnO:Sb films , exhibiting a threshold voltage of 0.8 V and reverse-bias leakage current was 0.1 uA . The X-ray diffraction shows that ZnO films are highly orientated along the (002) direction. Hall measurement indicated that the hole concentration was raised into high order of 1018cm-3 after cooled procedure. The optical transmission of the p–n junction sample was 60~80% in the visible region.
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Tsai, Wei-Che, and 蔡維哲. "P-N homojunction ZnO nanowire fabricated by hydrothermal synthesis for photoelectronic devices." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/95430870572700364128.
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碩士<br>國立中興大學<br>材料科學與工程學系所<br>104<br>N-type ZnO have been widely studied in the past decade,in recent years, many researchers had interest in researches of P-type ZnO nanowires for the further applications. On the other hand, p-n junction nanowire photosensors can enhance its sensitivity by breakdown bias application because of the avalanche effect.
In this study, phosphorus-doped ZnO nanowires were synthesized by Hydrothermal method with adding NH4H2PO4 in the synthesis solutions. The results show that the diameter and length of ZnO nanowires were both increased with the increasing of the concentration NH4H2PO4.The spacing of (0002) plane of P-doped ZnO nanowires increased by the addition of NH4H2PO4. Also, the slight red shift of UV emission peak in PL spectrum was observed. These P-doped ZnO nanowires have p-type semiconductor characteristic.
The p-n homojunction ZnO nanowires were grown using a two-step synthesis method. The rectifying and liner characteristics of p-n homojunction ZnO nanowires devices were achieved by electric field assembly with DC and AC electric field applications, respectively.Comparing with linear characteristic device, rectify characteristic device has higher sensitivity and shorter reaction time in the reversed bias application.
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HUNG, CHENG-WEI, and 黃承尉. "Study of ZnO Thin Film P-N Junctions Fabricated on Glass Substrates." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/bqrdbr.
Full textAbstract:
碩士<br>大葉大學<br>電機工程學系<br>105<br>In this study, we study the p-n junction which made based on the magnetron sputtering with the nitrogen as reaction gas, to grow ZnO thin films on glass substrate (Corning Eagle 2000). The first stage of this study is to grow p-type ZnO thin films with nitrogen doped. The total pressure of working gas is 150 mtorr. The working gas and the reaction gas are Ar and N2, respectively. The percentage of the N2 is 10% and 15% of the total working gas pressure. The thin films growing temperature is setting at 300 ℃ or 400 ℃. The deposited ZnO:N thin films were analyzed by XRD and found out that the thin films were epitaxial with c-axis perpendicular to the substrates. The resistivity, carrier concentration and carrier mobility of thedeposited thin films were measured by a Hall measurement system. The Hall coefficient of ZnO:N thin films which grow with 15 % of the reaction gas at 400 ℃ was positive, which indicated that thin films is p-type.
At the second stage, we use the ZnO thin films which deposited under the condition of the results of the first stage. Combine with photo lithography and wet etching to pattern the p-n junction. The junctions were measured by the semiconductor characteristics measuring instrument to explore the characteristics.