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1
Li, Feng 1967. "Characteristics of CuInSe₂ homojunction photodetectors." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31057.
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Studies have been made on homojunction photodetectors fabricated on Bridgman-grown monocrystalline p-type CuInSe2 substrates by diffusion of indium. The essential steps required to optimize the fabrication conditions were established.Firstly, parameters such as quantum efficiency, junction depth, surface recombination velocity, and minority carrier diffusion length are analyzed. Secondly, the dark current-voltage characteristics of devices were measured. Some detector dark current is only 80nA at 0.5V reverse bias. It was confirmed that the diffusion current and recombination current are comparable in the dark current transport mechanism of the CuInSe2 homojunctions. Thirdly, the relationships between capacitance-voltage, capacitance-frequency characteristics were also investigated. It was observed that at a given voltage, the capacitance value decreased when the measuring frequency was increased. This result confirmed that deep defects exist in the material. Fourthly, the diffusion length of minority carriers was determined by the photocurrent and capacitance method. The diffusion length is smaller than 1 micron. The quantum efficiency and photoresponse were also measured. The maximum quantum efficiency of the detectors was measured as high as 60%. The photodetector response time range from 14 mus to 21 mus.
2
Lee, Soon Peng. "Modelling the DC performance of GAAS Homojunction bipolar transistors." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/26306.
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Two models, one analytical and one numerical, have been developed to predict the dc performance of GaAs homojunction bipolar transistors. In each case the minority carrier properties of lifetime and mobility have been described by polynomial fits to recent data. Bandgap narrowing in the emitter and base regions has also been taken into account. The analytical model assumes uniform doping in the three regions of the transistor and is thus appropriate to predicting the performance of devices fabricated using epitaxial technologies. This model is also useful for carrying out sensitivity analyses. The importance of parameters such as regional widths and doping densities, minority carrier lifetimes and surface recombination velocity is examined here. The numerical model is useful for describing the performance of ion-implanted devices. Good agreement is obtained between results from the model and recent experimental data from prototype devices.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
3
Fisher, Martin John. "Epitaxial growth and characterisation of heterojunction and homojunction LEDs with InAs active regions." Thesis, Lancaster University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268062.
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Young-Waithe, Karen (Karen A. ). 1960. "Process design, development and fabrication of InAs homojunction converter cells for microscale thermophotovoltaic application." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/86597.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2001.Includes bibliographical references (p. 179-182).
by Karen Young-Waithe.
S.M.
5
Harada, Kentaro. "Organic p-i-n Homojunctions: Fundamentals and Applications." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1216987132976-99427.
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In this thesis, we study the physical properties of doped organic semiconductors. We first demonstrate the impact of doping on C60 films. In contrast to previous reports for organic thin films, the n-doped C60 films show a decrease of mobility with increasing doping levels; i.e., they follow the well-known Matthiessen rule which is generally observed in inorganic semiconductors. Using further strong organic donors and acceptors, we realize p-i-n homojunctions of several organic matrices: zinc-phthalocyanine, pentacene, and an iridium-complex TER004. We observe stable and reproducible diode characteristics, which can be described by the standard Shockley theory with an exception concerning the temperature dependence of the diode parameters. The current-voltage characteristics of the pentacene homojunctions under illuminated conditions indicate that the thermodynamic limitation of the open-circuit voltage is determined by the built-in voltage of 1.65 V, and that the recombination process is influenced by the distinct charge transport properties of electrons and holes. The very high built-in voltage of 2.2 V in the TER004 homojunction allows a red phosphorescent homo-OLED, which shows visible emission around 650 nm with low operation voltage. We examine the charge balance status in the homojunction structure, revealing that TER004 has superior electron transport properties.
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Сидор, О. М. "Гомоперехід n-InSe–p-InSe : Cd з ефективністю 2,8 %." Thesis, Сумський державний університет, 2015. http://essuir.sumdu.edu.ua/handle/123456789/40978.
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Шаруватий кристал InSe (група А3В6) є привабливим матеріалом для перетворювачів сонячної енергії внаслідок високої фоточутливості та оптимальної ширини забороненої зони (1,2 еВ). Додатковою перевагою є його висока радіаційна стійкість.
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Qiu, C. X. (Xing Xing). "Characteristics of ZnOCuInSe2 heterojunctions and CuInSe2 homojunctions." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65991.
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Baek, Kwang Ki. "Study of electrically active ceramic interfaces : ZnO based homojunctions and heterojunctions." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/11626.
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Piyankarage, Viraj Vishwakantha Jayaweera. "Uncooled Infrared Photon Detection Concepts and Devices." Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/phy_astr_diss/30.
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This work describes infrared (IR) photon detector techniques based on novel semiconductor device concepts and detector designs. The aim of the investigation was to examine alternative IR detection concepts with a view to resolve some of the issues of existing IR detectors such as operating temperature and response range. Systems were fabricated to demonstrate the following IR detection concepts and determine detector parameters: (i) Near-infrared (NIR) detection based on dye-sensitization of nanostructured semiconductors, (ii) Displacement currents in semiconductor quantum dots (QDs) embedded dielectric media, (iii) Split-off band transitions in GaAs/AlGaAs heterojunction interfacial workfunction internal photoemission (HEIWIP) detectors. A far-infrared detector based on GaSb homojunction interfacial workfunction internal photoemission (HIWIP) structure is also discussed. Device concepts, detector structures, and experimental results discussed in the text are summarized below. Dye-sensitized (DS) detector structures consisting of n-TiO2/Dye/p-CuSCN heterostructures with several IR-sensitive dyes showed response peaks at 808, 812, 858, 866, 876, and 1056 nm at room temperature. The peak specific detectivity (D*) was 9.5E+10 Jones at 812 nm at room temperature. Radiation induced carrier generation alters the electronic polarizability of QDs provided the quenching of excitation is suppressed by separation of the QDs. A device constructed to illustrate this concept by embedding PbS QDs in paraffin wax showed a peak D* of 3E+8 Jones at ~540 nm at ambient temperature. A typical HEIWIP/HIWIP detector structures consist of single (or multiple) period(s) of doped emitter(s) and undoped barrier(s) which are sandwiched between two highly doped contact layers. A p-GaAs/AlGaAs HEIWIP structure showed enhanced absorption in NIR range due to heavy/light-hole band to split-off band transitions and leading to the development of GaAs based uncooled sensors for IR detection in the 2 5 μm wavelength range with a peak D* of 6.8E+5 Jones. A HIWIP detector based on p-GaSb/GaSb showed a free carrier response threshold wavelength at 97 µm (~3 THz)with a peak D* of 5.7E+11 Jones at 36 μm and 4.9 K. In this detector, a bolometric type response in the 97 - 200 µm (3-1.5 THz) range was also observed.
10
Ariyawansa, Gamini. "Semiconductor Quantum Structures for Ultraviolet-to-Infrared Multi-Band Radiation Detection." Digital Archive @ GSU, 2007. http://digitalarchive.gsu.edu/phy_astr_diss/17.
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In this work, multi-band (multi-color) detector structures considering different semiconductor device concepts and architectures are presented. Results on detectors operating in ultraviolet-to-infrared regions (UV-to-IR) are discussed. Multi-band detectors are based on quantum dot (QD) structures; which include quantum-dots-in-a-well (DWELL), tunneling quantum dot infrared photodetectors (T-QDIPs), and bi-layer quantum dot infrared photodetectors (Bi-QDIPs); and homo-/heterojunction interfacial workfunction internal photoemission (HIWIP/HEIWIP) structures. QD-based detectors show multi-color characteristics in mid- and far-infrared (MIR/FIR) regions, where as HIWIP/HEIWIP detectors show responses in UV or near-infrared (NIR) regions, and MIR-to-FIR regions. In DWELL structures, InAs QDs are placed in an InGaAs/GaAs quantum well (QW) to introduce photon induced electronic transitions from energy states in the QD to that in QW, leading to multi-color response peaks. One of the DWELL detectors shows response peaks at ∼ 6.25, ∼ 10.5 and ∼ 23.3 µm. In T-QDIP structures, photoexcited carriers are selectively collected from InGaAs QDs through resonant tunneling, while the dark current is blocked using AlGaAs/InGaAsAlGaAs/ blocking barriers placed in the structure. A two-color T-QDIP with photoresponse peaks at 6 and 17 µm operating at room temperature and a 6 THz detector operating at 150 K are presented. Bi-QDIPs consist of two layers of InAs QDs with different QD sizes. The detector exhibits three distinct peaks at 5.6, 8.0, and 23.0 µm. A typical HIWIP/HEIWIP detector structure consists of a single (or series of) doped emitter(s) and undoped barrier(s), which are placed between two highly doped contact layers. The dual-band response arises from interband transitions of carriers in the undoped barrier and intraband transitions in the doped emitter. Two HIWIP detectors, p-GaAs/GaAs and p-Si/Si, showing interband responses with wavelength thresholds at 0.82 and 1.05 µm, and intraband responses with zero response thresholds at 70 and 32 µm, respectively, are presented. HEIWIP detectors based on n-GaN/AlGaN show an interband response in the UV region and intraband response in the 2-14 µm region. A GaN/AlGaN detector structure consisting of three electrical contacts for separate UV and IR active regions is proposed for simultaneous measurements of the two components of the photocurrent generated by UV and IR radiation.
11
Rinzan, Mohamed Buhary. "Threshold extension of gallium arsenide/aluminum gallium arsenide terahetrz detectors and switching in heterostructures." unrestricted, 2006. http://etd.gsu.edu/theses/available/etd-10102006-204618/.
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Thesis (Ph. D.)--Georgia State University, 2006.Title from title screen. Unil Perera, committee chair; Donald Edwards, Gennady Cymbaluyk, Mark Stockman, Nikolaus Dietz, Paul Wiita, committee members. Electronic text (348, 24-32 p. : ill.) : digital, PDF file. Description based on contents viewed June 8, 2007. Includes bibliographical references (p. 24-30, second sequence).
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Bruhat, Elise. "Développement de cellules photovoltaïques silicium à homojonction industrialisables à contacts passivés." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI128.
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Afin de favoriser le déploiement des énergies renouvelables, le développement de cellules solaires moins chères mais aussi plus performantes reste un enjeu pour rendre l’électricité photovoltaïque encore plus attractive. Si les technologies des cellules solaires à base de silicium à homojonction dominent le marché mondial, les performances de ces structures peuvent encore être améliorées. En effet, le contact direct entre la grille métallique et les zones fortement surdopées est source de pertes par recombinaisons des porteurs de charges. L’émergence de de nouvelles structures de cellules émergent à contacts passivés permet des solutions alternatives face à cette limitation. Ces structures visent à délocaliser la prise de contact grâce à l’introduction de couches passivantes entre le substrat de silicium cristallin et la grille de métallisation, diminuant ainsi drastiquement les phénomènes de recombinaisons au sein des dispositifs. La technologie de contacts passivés la plus connue reste celle des cellules à hétérojonction de silicium a-Si:H/c-Si. Cette technologie mature reste pour l’instant limitée car elle représente un nouveau standard industriel mais aussi car elle n’est pas compatible avec les procédés utilisant des températures excédant 250°C. De plus, l’utilisation d’indium, matériau cher et dont la ressource est limitée, dans les couches d’Oxyde Transparent Conducteur (OTC) peut représenter un frein à l’industrialisation de masse du procédé. Il est alors nécessaire de développer de nouvelles technologies de contacts passivés, compatibles avec des procédés à haute température (supérieures à 800°C), et donc intégrables dans une ligne de production existante. Des approches utilisant des OTC en combinaison avec des couches ultraminces d’oxydes, des empilements diélectriques, et des jonctions poly-silicium sur oxyde ont été investiguées afin d’améliorer les performances des cellules à homojonction. Les couches intermédiaires d’OTC développées permettent potentiellement de diminuer les pertes résistives et et celles par recombinaison au niveau des contacts. Ces travaux de thèse se sont ainsi focalisés sur le développement de couches d’oxyde de zinc dopé à l’aluminium (AZO) par pulvérisation cathodique (PC) et Atomic Layer Deposition (ALD) pour les cellules solaires à contact passivés. Ces couches, utilisées seules ou en combinaison avec des matériaux diélectriques, ont été intégrées et testées sur des dispositifs photovoltaïques fonctionnelsFor the deployment of renewable energies, the development of cheaper and more efficient solar cells remains an issue to make photovoltaic electricity even more attractive. While homojunction-based silicon solar cell technologies dominate the global market, the performances of these structures can be further improved. Indeed, the direct contact between the metal grid and the highly doped junction is a source of recombination losses. To overcome these limitations, new structures are emerging such as silicon-based passivated contacts solar cells. These structures aim at integrating of passivating layers between the crystalline silicon substrate and the metal grid, thus drastically reducing the recombination phenomena within the devices. Silicon heterojunction (a-Si:H/c-Si) cells remain the most well-known passivated contact technology. Nevertheless, this mature technology is still limited by its fabrication process which is far from the industrial standard, and is hardly compatible with temperatures exceeding 250 ° C. In addition, the use of expensive and potentially toxic indium in the Transparent Conductive Oxide (TCO) layers has restrained up to now the expansion towards mass industrialization of the process. Thus, it is necessary to develop new passivated contacts technologies compatible with high temperature (above 800°C), implementable in a standard production line. This study explores new paths for passivating contact technologies thanks to ultrathin layers of oxides or dielectrics/TCO stacks deposited on silicon homojunctions as well as poly-silicon on thin oxide junctions. In order to limit the resistive losses and potentially limit recombination losses in the contacted areas, intermediate TCO layers have been developed. In this perspective, this works aims at investigating the development of Aluminum Zinc Oxide (AZO) layers by both Magnetron Sputtering (MS) and Atomic Layer Deposition (ALD) for passivated contact solar cells. These layers, also used in combination with dielectric materials have been integrated and then tested in photovoltaic devices
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Glowacki, Frédérique. "Uhv-cvd : épitaxies, hétéro-épitaxies et dopages du silicium et de son alliage SiGe." Université Joseph Fourier (Grenoble ; 1971-2015), 1994. http://www.theses.fr/1994GRE10114.
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Ce manuscrit traite de la mise au point et des potentialites d'une nouvelle technique cvd utilisable avec des plaquettes de silicium de 200 mm de diametre et dont les applications concernent essentiellement les epi- et hetero-epitaxies de si et sige. L'objectif a ete double: (i) etudier une machine et son positionnement par rapport aux autres et (ii) developper des procedes dans ce prototype. La technique uhv-cvd retenue est basee sur l'ultravide pour garantir un taux de contamination et de fuite minimum et pour pouvoir travailler en regime de gaz moleculaire ( 10#-#3 torr). Apres avoir decrit le contexte ayant preside au choix technique de la machine fabriquee par riber, celle-ci est presentee avec ses principales fonctionnalites et limites techniques. Cette machine etant un prototype en perpetuelle amelioration, il a fallu developper dans le meme temps des procedes typiques comme l'epitaxie de si (dope ou non) et l'hetero-epitaxie de sige. Pour valoriser cette technique, des structures comparables a celles obtenues soit par mbe soit par cvd dans les autres gammes de pression ont ete realisees. Les resultats materiaux sont au moins comparables sinon meilleurs a ceux publies dans la litterature: transistors bipolaires a heterojonction, multi-puits quantiques, gaz bidimensionnels de trous parallelement a ces etudes, l'ellipsometrie spectroscopique (es) in-situ a ete utilisee comme outil de caracterisation non destructif. Les resultats obtenus pour differentes applications montrent que l'es (i) s'imposera dans les futurs reacteurs mono-plaque et (ii) qu'elle pourra fournir les indices optiques du si et sige a toute temperature au dessus de l'ambiante. Enfin, cette technique d'uhv-cvd (equipement et procedes) doit se confronter a celles en cours de developpement ou deja presentes sur le marche des semi-conducteurs. Les differents avantages et positionnements possibles de cette technique sont donc abordes
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Wu, Jan-Rung, and 吳展榮. "Fabrication of Homojunction Cu2O Solar Cells." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/q33bvq.
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碩士國立東華大學
光電工程學系
102
Cu2O p-n homojunction solar cells were electrochemically fabricated by consecutively depositing an n-Cu2O layer on a p-Cu2O layer. First, the investigation of n-type and p-type Cu2O thin films, which were grown in the acidic and basic electrolyte, respectively, were systematically examined by X-ray diffraction and scanning electron microscopy (SEM). Significantly, the photoelectrochemical analysis, such as photocurrent response and open circuit potential under light illumination, clearly demonstrated the n type and p type semiconducting natures of Cu2O thin films. Furthermore, the homojunction of p-n Cu2O solar cells were subsequently deposited the p-type and n-type Cu2O on the ITO substrate. The thicknesses of the p-type and n-type Cu2O film were controlled by the coulomb numbers during the film growth. The effect of the film thickness on the device performance was investigated by the cross-section SEM, I-V curves, and external quantum efficiency. According to our results, the optimum conversion efficiency of 0.42 % in the Cu2O solar cell was achieved under the growth coulomb number of 0.208 C and 0.135 C for p-type and n-type Cu2O film, respectively. From this study, the Cu2O homojunction device by using easy fabrication exhibits greater potential in photovoltaic solar cell application.
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侯貴凱. "Efficient white light emission in conjugated polymer homojunction." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/98xydm.
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碩士國立交通大學
物理研究所
92
In my thesis, we discussed a new method to make white polymer light-emitting diodes by improving the structure of devices. It can achieve high-efficiency and high-luminance. There are many ways to achieve white polymer LEDs, include polymer blends; exciplex in bilayers, phosphorescent Ir complex; polymer dope with dyes. But these yield and luminance are not yet achievable for application of manufactures. We use two steps to make our device: (1)multi-layer and (2)polymer blend. It can make organic material to produce homojunction like inorganic semiconductor. And it also has the advantages of large area and solution process. In this structure, the peak luminance of our white polymer LEDs can achieve over 10000 cd/m2, and the pick yield can achieve almost 3cd/A.
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Hung, Chun-fang, and 洪春芳. "The investigation of doping and homojunction for ZnO." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/cdmbuq.
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Huang, Yu-Hung, and 黃昱閎. "N-type silicon based homojunction and heterojunction solar cells." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/83478367825654828285.
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碩士國立臺灣大學
電子工程學研究所
99
Wafer based solar cell accounts for the production of a large part in photovoltaic industry due to its stability and high efficiency. Although the technology of wafer based solar cell has been well-developed for conventional structure, there are still numerous new challenges existing for high efficiency solar cell. In this thesis, the fabrication process of n-type silicon based homojunction solar cell is demonstrated by using ion implantation to form the boron (p+) emitter and phosphorous (n+) back surface field. By using appropriate annealing condition, The implanted dopants and damage introduced by implantation can be activated and repaired, respectively. Both rapid thermal annealing (RTA) and furnace annealing were investigated within this work. The efficiency is 14.5% by RTA process and 15.8% by furnace annealing process. Moreover, contact formation, contact material, and contact thickness conditions are taken into consideration for better efficiency. Therefore, experiments of various annealing conditions in forming gas after depositing contact, different material, and the thickness of contact are designed in this work. Next, surface passivation is very important for solar cell efficiency due to its strong dependence on open circuit voltage so it affects solar cell efficiency. Aluminum oxide (Al2O3) layers deposited by different method are compared for passivation ability by using quasi-steady-state photoconductance and photoluminescence (QSSPC) measurement. It means better passivation ability to passivate solar cell for higher effective carrier lifetime. In addition, QSSPC measurement also provide a way to estimating the implied open circuit voltage after forming the junction of solar cells. With the excellent passivation of Al2O3 deposited by atomic layer deposition (ALD), the efficiency more than 16% is shown in this work. Finally, the n-type silicon HIT solar cell with 11.1% efficiency is demonstrated to discuss the benefits from amorphous silicon emitter and suitable PDA condition.
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Huang, Ku-jen, and 黃谷任. "The fabrication of GaAsP/GaP homojunction diodes by LPE." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/04537306694394555816.
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碩士中原大學
電子工程學系
87
Ⅲ-Ⅴ ternary semiconductor alloy crystals are of vital importance in fabrication of optoelectronic and high-speed devices since the expected band-gap energy and lattice constants can be achieved simply by controlling their composition. The GaAs1-xPx alloy systems have a wide-range variation of energy gap. It has been reported that a GaAs layer grown on a GaP substrate changes its composition to GaAs1-xPx when it is put in contact with a Ga-As-P solution. According to our previous studies, the conversion process mentioned above stops at the surface of the GaP substrate, leaving a GaAs1-xPx layer on the GaP substrate with x ranging from 0.25 to 0.75, where x can be controlled by the growth time. In this study, we use the above-mentioned growth method, so called "composition conversion" technique to grow GaAsP/GaP p-n homojunction diodes. This work is divided into two parts. First, the p-type doping amount and the n-type doping amount are systematically investigated. Nomarski microscopic analysis, X-ray diffraction, photoluminescence and Hall measurements are used to evaluate the quality of both p- and n-type epilayers. Second, GaAsP/GaP p-n homojunction diodes are fabricated. Current-voltage (I-V) measurement is used to analyze its electrical properties and electroluminescence (EL) measurement is used to characterize its optical properties. It is found that a p-n homojunction diode with the ideal factor n = 1.1 at cut-in voltage = 1.1V has been achieved. Besides, EL measurement has confirmed the luminescent characteristics of these diodes. This study indicates for the first time the possibility of fabricating a GaAsP/GaP(111) homojunction diode by liquid-phase epitaxy.
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Lin, Li-Wei, and 林理偉. "Simulation and analysis of InGaN single homojunction solar cells." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/27956624744141793823.
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碩士國立彰化師範大學
光電科技研究所
99
We have only one earth. People are more and more intense on the demand of "clean energy". Owing to the accident that happened to the first nuclear power plant in Fukushima on March 11, 2011, people doubt the reliability of "clean nuclear energy" and hence pay more attention to the development of solar energy. InxGa1-xN alloys with wide energy band gap, which ranges from 0.7 eV to 3.4 eV, can cover most of the solar spectrum. Therefore, it is possible to produce a full solar-spectrum and high-efficiency solar cell based solely on the nitride materials. As a result, the single p-n homojunction InGaN solar cell was investigated numerically in this thesis. In chapter I and Chapter II, brief introductions to the development history of solar cells and the research status of InGaN solar cells were made. Besides, some basic principles of solar cells, the characteristics of nitride material, and the properties of nitride-based solar cell were also included as a theoretical basis of this paper for the subsequent study. The relevant references were also provided. In chapter III and chapter IV, several different structures were investigated to enhance the device performance and probe into the physical mechanism. The major subjects under study include thickness of p-layer, thickness of n-layer, thickness of graded-layer, degree of relaxation (degree of polarization effect), and thickness of graded-layer under polarization effect. Finally, an optimized structure was proposed. Chapter V is the summary of this thesis. The simulation results of the optimal structure were marshaled. At last, a description about the possible direction of future work was made.
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Lin, Chu-Che, and 林炬徹. "Fabrication of titania electrodes with a p-n homojunction." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/15404542220405420875.
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碩士元智大學
化學工程與材料科學學系
94
The research designed and fabricated a p-n homojunction multiple titania layers electrode. First, fabricating nano-titania electrode by sol-gel method and doping metal ions ( Fe3+、Cr3+ ) changed electrode characteristic to fabricate P-type ceramic semiconductor. At last, the p-n junction multiple titania electrode composed of P-type titania doped metal ions and N-type ceramic semiconductor fabricated by commercial powder P25. The result showed that material properties of titania doped metal ions was different from pure titania. The I-V curve perform clear rectification when giving a doping metal ions ( Fe3+、Cr3+ ) level was 0.25mole% after sintering 4000C. It also influenced electrode I-V curve characteristic by doping different kinds of metal ions and coating different thickness of film. The p-n junction titania electrode designed by the research certainly perform clear rectification to P25 titania electrode. We hope it could improve the efficiency of electrode transmtting electron by the electric field force formed with p-n junction. Finally, reaching the purpose to improve the efficiency of dye-sensitized solar cell.
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Cheng, Yu-Chih, and 鄭宇智. "Fabrication of Homojunction Photodetectors withPhosphorus-Doped Zinc Oxide Nanorod Arrays." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/w3k7t6.
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碩士國立虎尾科技大學
光電與材料科技研究所
103
In this study, the production of zinc oxide nanorods homogeneous light sensor to study the theme, the use of inexpensive and simple hydrothermal method, zinc oxide is doped with different concentrations of phosphorus and how to successfully make stable and good characteristics of P-type oxide zinc, and then stacking undoped zinc oxide, and make it a PN junction, complete a homogeneous light sensors to reduce lattice mismatch and so distortion caused. The main research can be divided into two parts: The first part: using RF-magnetron sputtering machine on a glass substrate by sputtering a layer of zinc oxide thin film as a seed layer after, arranged into different percentages by weight of phosphorus was grown until the growth is completed, i.e., into the deionized water clean the surface, after cleaning the surface of the specimen using a rapid thermal anneal processing, followed by Hall measurement (HALL), secondary ion mass spectrometry (SIMS), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS ) on the state of phosphorus doping analysis, and to explore the doping concentration is good, then used X-ray diffraction spectrum analysis (XRD), UV - visible spectrophotometer (UV-VIS), fluorescence spectroscopy (PL), Phosphorus-doped zinc oxide nanorods were analyzed to explore the characteristics of the preferred concentration. Part II: The better the properties of phosphorus-doped substrate into the solution using a hydrothermal growth of ZnO nanorods, stacked on top of phosphorus-doped zinc oxide to form a PN junction, and then use an environmental scanning electron microscope ( SEM) surface structure analysis, analysis after column coated with zinc oxide nano-silver plastic, when the electrode used, and using a solar simulator IV measurement and parameter measurement system analysis, comparison can be found in the doping concentration influence the elements very big, too much will make the characteristic decline doping, doping will make features can not be too out of the analysis of the future impact is far-reaching element of it is doped with phosphorus.
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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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碩士國立高雄第一科技大學
光電工程研究所
101
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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Li, You-He, and 李佑禾. "An Investigation on Ag-ZnO Films and Fabrication on Homojunction Diode." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/as742s.
Full textAbstract:
碩士國立虎尾科技大學
光電工程系光電與材料科技碩士班
105
In study,Ag dope ZnO films and undoped ZnO films were prepared by RF magnetron co-sputtering system by Ag and ZnO tragets,using annealing system activates the dopant atoms in the films.The results showed that the undoped ZnO exhibits n-type conductive,and Ag-ZnO exhibite p-type conductive.By XRD diffraction spectra, the peak position of the Ag-ZnO films are lower than normal ZnO (002) peak position of 34.36°.This is caused by Ag ions replaves the Zn ions,because which Ag radius greater than Zn radius.The current-voltage characteristics,Ni/ITO and ITO-ZnO as electrode deposition of p-type and n-type present ohimc contact.In this study, we fabricated p-ZnO/n-ZnO homostructures diode on silicon substrate，In current-voltage characteristics,when the voltage is positive or negative 2.5 V,the current ratio is about 0.96,which shows no rectifying characteristcs,deposited Ni/ION above surface p-n diode,showing the schottky contact,that the p-type ZnO transforms into n-type conductive. XPS diagrams show that when Ag-ZnO and n-ZnO contact, Ag-ZnO film found that Ag atoms are in the metallic state in thin film. In the middle of the Ag-ZnO and n-ZnO added a layer of i-ZnO From the Raman spectra,found that p-i-n ZnO homostructures at 412 cm-1 peak significantly. The p-type ZnO deposited at the top of the i-ZnO/n-ZnO, and the silver atoms replaced the zinc atoms. in the p-type ZnO film In current-voltage characteristics,Ag-ZnO/i-ZnO/n-ZnO homojunction diodes exbihit poor rectifying characteristics,and the diodes turn-on voltage of about 1.69 V.In order to optimize the homojunction diode,change the i-ZnO into a double hetero-junction(AlN-ZnO/ZnO/AlN-ZnO;DH) structure with different active layer of thinckness. XPS diagrams show that Ag-ZnO deposited on the DH/n-ZnO surface, p-type ZnO have that Ag atom is silver and oxygen bond balance in a thin film, maintenance of p-type ZnO. Reducing the thickness of the active layer from the current-voltage measurements found to reduce the series resistance and turn-on voltage.When the double DH is add,the current ratio is higher than p-i-n homojunction diodes.The thermionic emission theory and Cheung’s formula to explore the ideal factor and Schottky barrier.
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Ding, Jun-Xin, and 丁俊馨. "Study of fabrication of oxygen doped molybdenum disulfide pn homojunction diode." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/03713454115687311855.
Full textAbstract:
碩士國立臺灣科技大學
電子工程系
105
In this thesis, a large area of n-type molybdenum disulfide (MoS2) was fabricated by thermal chemical vapor deposition (CVD). The results of Raman spectrum, photoluminescence (PL) and atomic force microscope (AFM) showed that the synthesized MoS2 was single layer and direct bandgap semiconductor material. To transform the characteristics of MoS2 from n-type to p-type, the oxygen plasma treatment with different radio-frequency (RF) powers was conducted. X-ray photoelectron spectroscope (XPS) analysis showed that the peak of Mo6+ mainly changed the properties of MoS2 from n-type to p-type, resulting from the surface formation of MoO3. In the field effect transistor (FET) measurement, as the MoS2 treated with the RF power increased, the current-voltage (I-V) curve of the lowest point shifted from -45 to 50 V, confirming the MoS2 changed from n-type to p-type successfully. In order to fabricate a homojunction pn diode, we defined a plasma treatment region with a mask on MoS2 surface for doping accurately. The I-V characteristic was measured to analyze the pn diode, and the built-in potential barrier was shifted from 2.7 to 4.3 V. Therefore, the built-in potential barrier could be controlled with different RF powers. Furthermore, the MoS2 homojunction pn diode demonstrated good rectification behaviors, we expect that it can be widely applied in the future.
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You-Ren, Wu, and 吳友仁. "Investigation of Homojunction and Heterojunction Camel-Like Gate Field-Effect Transistors." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/44476681222414885556.
Full textAbstract:
碩士國立高雄師範大學
電子工程學系
101
Investigation of Homojunction and Heterojunction Camel-Like Gate Field-Effect Transistors You-Ren Wu* Jung-Hui Tsai** Department of Electronics, National Kaohsiung Normal University, Kaohsiung, Taiwan, R.O.C Abstract In this thesis, we will use the development of simulation software to studied homojunction structure camel-like gate field-effect transistors and heterojunction structure camel-like gate field-effect transistors, in order to obtain better DC and high frequency characteristics,etc. First, the Silvaco software is employed to simulate the characteristics of the GaAs homojunction camel-gate field-effect transistors (device A) without the gate-to-source and gate-to-drain recess, and to compare the same transistor (device B) with recessed structure between gate-to-drain and gate-to-source region. The device A appears a second channel within the n+-GaAs cap layer resulting from the parallel conduction. Thus, a two-stage current and transconductance versus gate voltage are observed. Simulated results exhibit the characteristics of the device A (device B) with a gate barrier height up to 1.14 eV (1.14 eV), the transconductance of 525 mS/mm (148 mS/mm), a maximum saturation output current density approximates 447 mA/mm (351 mA/mm), a turn-on voltage up to 0.97 V (1.525 V), a unity current gain cut-off frequency of 9.6 GHz (9.1 GHz), and a maximum oscillation frequency are 13.7 GHz (13.5 GHz), respectively. In chapter 2, we studied the influence of channel concentration on GaAs homojunction camel-like gate n-channel field-effect transistors. Two devices have not recess structures and the channel concentration is changed from n = 1 1018 cm-3 (device A) to 1 1017 cm-3 (device C). For the device C, the results exhibit the gate barrier height only 0.65 eV, the transconductance of 137 mS/mm, the maximum saturation output current density of 29.5 mA/mm, the turn-on voltage of 0.965 V, the unity current gain cut-off frequency of 7.4 GHz, and maximum oscillation frequency of 11.6 GHz, respectively. III-V heterojunction field-effect transistors in digital and microwave circuit applications provide a promise of potential development. In chapter 4, we will focuse on the InGaP/GaAs or AlGaAs/GaAs camel-like gate heterojunction field-effect transistors, which has a large energy-gap InGaP or AlGaAs layer to endure a maximum electric field for endurancing gate breakdown voltage. In addition, the conduction band discontinuity (△Ec) at heterojunction with good confinement effect for electrons in channel can achieve a larger gate turn-on voltage, drain -source current, and transconductance. According to the simulation results, the device D (InGaP/GaAs camel-gate FET) and device E (AlGaAs/GaAs camel-gate FET) show barrier heights up to 1.13 eV and 1.28 eV, maximum transconductances of 477 mS/mm and 476.8 mS/mm, maximum saturation output current densities of 207.8 mA/mm and 207.8 mA/mm, gate turn-on voltages up to 0.96 V and 0.97 V, unity current gain cut-off frequencies of 6.13 GHz and 6.1GHz, and maximum oscillation frequencies of 10.5 GHz and 8.95 GHz, respectively. * Author ** Advisor KEYWORDS: parallel conduction, InGaP/GaAs, AlGaAs/GaAs
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Bonnet, Wayne. "Scaling and Optimization of Polymer Bulk Homojunction Light-Emitting and Photovoltaic Cells." Thesis, 2008. http://hdl.handle.net/1974/1428.
Full textAbstract:
The polymer light-emitting electrochemical cell (LEC) is an alternative method for producing electroluminescence (EL) from conjugated luminescent polymers. The in situ electrochemical doping process that leads to a dynamic p-n junction makes the devices highly insensitive to device thickness and relatively insensitive to electrode materials. These characteristics make an extremely large planar configuration accessible for observing the cross-section of the device and watching it turn on dynamically. By cooling the device to freeze ionic motion, the junction can be stabilized and photovoltaic (PV) characteristics investigated. In the planar configuration, the p-n junction was found to make up a small fraction of the inter-electrode spacing. Enabled by the insensitivity to electrode materials, small metallic particles embedded in the LEC film led to a large number of p-n junctions that could be turned on in series and parallel. This alleviates the issue of low specific emitting area suffered by planar devices and leads to improved EL effciency as well as a high open circuit voltage (Voc) when operated as a PV cell. The bulk homojunction fabrication process has been optimized by segregating the metallic particles to eliminate large aggregates. A new technique to achieve highly uniform EL from large planar LECs is also presented here. By the evaporation of a thin gold or silver film on top of an LEC, independent islands form that act as doping initiation sites across the device width. A bulk homojunction is turned on in the top layer of the LEC with a high applied bias. Island diameters and spacings are several orders of magnitude smaller than the particles in previously-reported bulk homojunction devices. Both island and particle devices had their interelectrode spacings scaled down by at least a factor of 10. The successful scaling is a promising result for the possibility of a sandwich configuration bulk homojunction device. In the case of silver island devices, cooling a 50-micron wide device after turn-on resulted in a PV cell with an open circuit voltage of 8.3 V, several times the band gap of the luminescent polymer used.Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2008-09-12 12:21:12.949
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Huang, Jun-Lin, and 黃俊霖. "Characterization of Photovoltaic Performances of InGaN p-i-n Homojunction Solar Cells." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/00412685897949104086.
Full textAbstract:
碩士中原大學
電子工程研究所
98
With the emergency of global energy crisis, photovoltaic technology of solar cell has become a hot research field. Although significant progress has been achieved, improving the conversion efficiency is still the main task. One approach is to make the solar cell absorb as much as possible the solar spectrum. The alloy of InGaN is direct bandgap material and its bandgap covers the most of the solar spectrum, from 0.65 to 3.4 eV by adjusting the In content. It thus has substantial potential in developing high-efficiency.full-spectrum-response solar cell based solely on nitride-based materials. Additionally, its high absorption coefficient of approximately 105 cm−1 at the band edge makes it absorb the most of the incident light only in a few hundred nanometers, which is beneficial to reduce the thickness of device. Recent studies confirm its substantial potential in photovoltaic applications and demonstrate its favorable photovoltaic properties, such as low effective mass, high carrier mobility, high saturation velocity, high temperature resistance, and superior radioresistance.13 Up to now, InGaN/GaN heterojunction and InGaN homojunction structures have been used.
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Wei-DaWang and 王威達. "Study of CuIn1-xGaxSe2 Homojunction Formation by Annealing ZnS/CIGS Thin Films." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/14985190371096528351.
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Sheu, Tian-Syh, and 許天賜. "Homojunction and Heterojunction LightEmitting Diodes of Poly-(N-vinylcarbazole)and Dye Molecules." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/49140787231819178898.
Full textAbstract:
碩士國立中山大學
材料科學研究所
89
ABSTRACT Organic light emitting diode (OLED) has significant scientific implication and technological potential. Using organic materials for tailored emitting color, threshold voltage reduction, and emission efficiency gain are the key points for the commercialization of OLED. An UV-Vis spectrophotometer was applied to obtain the absorption spectra of PVK, C6, and PRL, as well as their respective band gap (Eg) values of 3.49 eV, 2.32 eV, and 2.55 eV. The turn-on oxidation potential of cyclic voltammograms was reduced for HOMO energy at 5.64 eV, 5.21 eV, and 5.16 eV, respectively. The Eg subtracted from HOMO energy yielded the respective LUMO values of 2.15 eV, 2.89 eV and 2.61 eV. Excitation at 457 nm or 325 nm was applied to the freestanding films of PVK, PVK doped with C6 (10/1), and PVK doped with PRL (10/1). From the UV-Vis absorption spectra and Egs, we knew that 457 nm excitation did not generate photoluminescence (PL) of PVK. The PL spectra of the doped freestanding films were mostly attributed to the dye molecules of C6 or PRL. The PL spectra of doped freestanding films were insensitive to the excitation sources at 325 nm and 457 nm. There was a blue shift at the PL emission peak indicative of energy transfer from PVK to C6 or PRL for the doped films. Using spin-coating or vacuum deposition to fabricate PVK, C6, and PRL films onto an ITO substrate followed by evaporating Al (Ag) as the electron injector to form OLED devices. Because of the energy transfer between PVK and C6 or PRL, ITO/PVK:C6/Al homojunction OLED showed a smaller threshold voltage than that of ITO/C6/Al, from 9 V to 3.5 V. Likewise, ITO/PVK:PRL/Al homojunction OLED had a smaller threshold voltage than that of ITO/PRL/Al, from 8 V to 4.5 V. PVK was also used as the hole blocking layer to construct heterojunction OLED to balance electron-hole numbers in the emitting layer. The threshold voltage of ITO/C6/Al reduced from 9 V to 7 V with a heterojunction of ITO/PVK/C6/Al. A device of ITO/PRL/Al having a threshold voltage of 8V reduced to 6V with an ITO/PVK/PRL/Al heterojunction OLED. Coating a protective layer (Ag) on the metallic electron injector, or packaging the device in N2 could both decrease the decay and increase the life time of OLED.
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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.
Full textAbstract:
碩士國立中興大學
材料科學與工程學系所
104
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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莊宗澔. "Sputtered Indium Nitride as an Adhesive Layer for Homojunction and Heterojunction Wafer Bonding." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/42sym2.
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Yang, Wan-Ting, and 楊婉婷. "Fabrication and application of multi-layer graphene pn homojunction diode with nitrogen doping." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/92664k.
Full textAbstract:
碩士國立臺灣科技大學
光電工程研究所
105
Graphene is a two dimensional material with high surface area and high carrier mobility. Graphene is an attractive candidate for potential applications in optical and electrical devices due to these outstanding properties. Pristine graphene usually exhibits p-type behavior owing to the adsorption of oxygen and water vapor from the air. Therefore, modulating the grapheme electronic structure is an essential issue. Nitrogen doping is a facile approach used to tune the Fermi level above the Dirac point. Multi-layer graphene was synthesized in this study using chemical vapor deposition and then treated using nitrogen plasma. Under nitrogen plasma exposure the lateral graphene p-n junction was formed with the mask defining the doping regime. We investigated the device electrical characteristics using the half-wave rectifier. By modulating the nitrogen plasma power the current-voltage curve shows the Dirac point shifted from a positive value (+75 V) to a negative value (-55 V), indicating successful grapheme transformation into an n-type semiconductor. The nitrogen content increased from 1.4% to 2.8% with increased power. Pyrrolic-N content increased leading graphene FET to act as an n-type semiconductor. As shown from the Raman spectrum, the doping process induced defects. The graphene lateral homojunction exhibited diode properties. Good rectifier performance with very low distortion was identified by the oscilloscope. This device could be further applied in metal-oxide-semiconductor field-effect transistors and bipolar junction transistors.
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Tsai, Jyun-Jhang, and 蔡均璋. "Fabrication and Characterization of ZnO-Based Thin Film Homojunction by Sol-Gel Method." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/23385496516426245935.
Full textAbstract:
碩士國立高雄第一科技大學
電機工程研究所碩士班
103
The study of this thesis is focused on the fabrication and characterization of ZnO p-n homojunction prepared by sol-gel method. We investigated the influences of process parameters on the ZnO and NAZO thin films as well as tried to identify the key factors of these influences. By investigating the electrical properties, optical properties, surface morphology and microstructure of the films influenced by the process parameters, we can produce a p-n homojunction with I-V curve of distinct rectification. In this thesis sol-gel solution of ZnO was prepared by dissolving zinc acetate in ethanol with added ethanolamine as stabilizer and stirred to obtain transparent solution. NH4OH and NH4Cl were selected as nitrogen source. Aluminum chloride (AlCl3) was then used as an aluminum dopant to produced p-type ZnO:Al thin film. Finally, the pyrolysis of an organic solvent was conducted by heat treatment in a rapid annealing furnace. The influence of dopant concentration and annealed temperature on structure and properties of ZnO films was studied. It was found that high temperature, layer by layer annealing and aluminum dopant concentration are all crucial to the ZnO films with high crystalline and preferential c-axis orientation. Based on the developed sol-gel method, we have successfully produced the n-ZnO nanopillar/p-NAZO homojunction with Vturn-on 1.6 V, ideal factor 2.5. and the transmittance in visible light area over 86 %. It is promising for the future developments of UV detector applications.
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Ma, Chih-Kang, and 馬智綱. "Semiconductor characterization of P-N homojunction TiO2 films using metal-ion doped technology." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/89242551768134519407.
Full textAbstract:
碩士元智大學
化學工程與材料科學學系
95
Abstract A nano-TiO2 electrode with a p-n homojunction device was designed and fabricated by coating of the nano-TiO2 (n-type) film together with the metal ions-doped TiO2 films. The sample films were prepared with synthesized sol-gel TiO2 which were verified as nano-size particles with anatase structure. The semiconductor characteristic of the sample films was analyzed by current-voltage measurement. Results show that the rectifying characteristic of the TiO2 films was observed from the I-V data illustration for the sample films. In addition, the characteristic of the rectifying curves was influenced by the fabricated conditions of the films, such as the doping concentration of different kinds of metal ions, heating temperature of the films, films thickness and device designed. Furthermore, a MOS device was designed and fabricated using the results in this study. Keywords：TiO2 electrode, p-n homojunction, dope, I-V measurement, metal ion
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Furukawa, Melissa. "Control of Dopant Type and Density in Colloidal Quantum Dot Films." Thesis, 2012. http://hdl.handle.net/1807/32242.
Full textAbstract:
Colloidal quantum dots (CQDs) are an inexpensive and solution processable photovoltaic(PV) material reaching modest efficiencies of 6%. However, doping quantum dots still remains a challenge. This thesis explores the level of doping in lead sulfide (PbS)CQDs by surface ligands and bulk doping within the quantum dot lattice using metals.
In light of the knowledge that oxygen creates traps on the surface of PbS CQDs, we
have turned to the use of oxygen-free fabrication. We find that under a nitrogen environment, PbS CQD films are n-type and tunable in doping by use of halide ions. We show for the first time control over the doping density of n-type CQD films over a wide range. We also show the ability to fabricate p-type PbS films with high doping
density that are compatible with n-type films. This compatibility enabled us
to make the world’s first CQD homojunction PV device.
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Liao, Hung-chi, and 廖弘基. "Package of Homojunction of Fully Conjugated Heterocyclic Aromatic Rigid-rod Polymer Light Emitting Diodes." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/63268434698308493072.
Full textAbstract:
碩士國立中山大學
材料科學研究所
92
The focus of this study is mono-layer polymer light emitting diode (PLED). The emitting layer is poly-p-phenylenebenzobisoxazole (PBO). PBO is a fully conjugated heterocyclic aromatic rigid-rod polymer. Anode is indium-tin-oxide (ITO). Cathode is aluminum (Al). We used UV epoxy resin to package PLED devices, then measured current-voltage response, electroluminescence (EL) emission, and device lifetime. We demonstrate that the packaged mono-layer PBO LED reduced its demise from water and oxygen. Device lifetime increased from 1 hour to several hundred hours. At a larger bias voltage or current, emission intensity and device efficiency became higher. But decay rate increased leading to shortened device lifetime. Device temperature appeared linearly with current density. A red shift of the EL emission was observed. The λmax. of emission spectra moved from 534 nm (initial) to 582 nm (after 100 hrs). After thermal annealing at 120℃ for ten hours, threshold voltage increased from 5 V to 12 V, current density decreased to several 10 mA/cm2, luminous intensity improved several ten times to 10-2 cd/m2, emission color changed from yellow-green to orange, luminous efficiency improved from 10-7 to 10-4 cd/A, but device lifetime declined to less than 20 hrs.
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Lin, Chia-Te, and 林家德. "Study on the growth and characterization of InAsSbP homojunction diodes by liquid phase epitaxy." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/38616407733970516441.
Full textAbstract:
碩士中原大學
電子工程學系
87
Abstract InAsSbP quaternary alloys lattice-matched to InAs substrate are promising materials for 2-4um wavelength optical sources. By using a supercooling technique of LPE, quaternary alloys of InAsSbP are successfully grown on the (100) InAs substrate. It is indicated that the amounts of supercooling temperatureΔT adopted have dramatic effects on both the carrier concentration and the surface morphology of the grown epilayer. A quaternary InAsSbP (x~0.094, y~0.06) layer with mirror-like surface and flat interface can be obtained by the use of supercooling temperature ΔT=10℃. A low background concentration of 5x1016cm-3 from the Hall measurements is achieved for these quaternary epilayers. The lattice-mismatch between the epilayer and the substrate is estimated as only -0.038% by x-ray diffraction. The InAsSbP diodes are successfully fabricated and their electrical properties are measured. It is found that the dark current is dominated by different mechanisms as the temperature range varies. When T>180K, the dark current is dominated by the diffusion mechanism; when T in the range between 140K and 180K, the generation-recombination mechanism comes to dominate; and when T<140K, the tunneling mechanism dominates the dark current. The temperature dependence of RoA product of the InAsSbP diodes is measured. The value of RoA is about 2.9x106Ω-cm2 when the temperature reaches 80K and it degrades to 6555Ω-cm2 when the temperature is raised to higher than 220K. From the I-V characteristics, it demonstrates a forward bias turn-on voltage of 0.06V with an ideality factor of 1.1 at 300K. The breakdown voltage of the diodes is about -2.3V. From the room temperature C-V characteristics, the junction capacitance of diode is 315.2pF and the potential voltage is estimated to be about 0.28V.
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Jhan, Jia-Lin, and 詹佳霖. "Investigation of p-n Cu2O homojunction diodes fabricated using electrochemical deposition and rapid thermal annealing methods." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/03301061337441971168.
Full textAbstract:
碩士元智大學
化學工程與材料科學學系
104
Cu2O-based p-n homojunction diodes were designed and fabricated using electrochemical deposition and rapid thermal annealing (RTA) methods. P-type Cu2O (p-Cu2O) films were prepared by the electrochemical deposition in a base solution under constant current settings; whereas, n-type Cu2O (n-Cu2O) films were made in an acid solution. The Cu2O-based diodes were further fabricated by the deposition and the RTA methods applied in the processing of the p-Cu2O and n-Cu2O films. Results show that the Cu2O film surface became more uniform when the pt web was used as an electrolyte in the electrochemical deposition system. The properties of both Cu2O films, such as surface structure, crystal, and electronic properties were greatly influenced by the RTA treatment. The conductivity, the particle and crystal sizes of both Cu2O films apparently increased as the RTA temperature increased. Additionally, different types of the Cu2O homojunction diodes were further fabricated on the basis of the p-Cu2O and n-Cu2O processing. The device performance was measured and analyzed to obtain better diodes. Keywords: Electrochemical deposition, cuprous oxide, p-type Cu2O, n-type Cu2O, diode.
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Keng-YiSu and 蘇耕毅. "A Study of Formation pn-Homojunction Diode by Diffusion of ZnS into CuIn1-xAlxS2 Film via Sulfurization." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/50428614611183337982.
Full textAbstract:
碩士國立成功大學
微電子工程研究所碩博士班
101
In this thesis, the CuInAl metallic precursors were deposited by sputtering. The composition ratio of the precursors and how the layers were stacked will influence the grain size and morphology of the post-selenized film. In my experiment, three different stacking methods were tried to deposit the precursors. Among them, sputtering Al first and then co-sputtering Cu-In is the best to form CuInAlSe2 (CIASe) film with large grain size after a selenization process. The CIASe film can be transformed to a CuIn1-xAlxS2 (CIAS) film after a high temperature sulfurization process. The formulated CIAS film is a p-type material. In the experiments, the sulfur can replace selenium easily and the original morphology can be kept after the sulfurization. The band gap of a CIASe film is from 1 eV to 2.7 eV. The band gap of a CIAS film is from 1.5 eV to 3.5 eV. Sulfurization and composition of aluminum are keys to modulate the CIAS film’s band gap which is suitable for tuning the emitting wavelength of the light for light emitting diode (LED) applications. After formulated the p-type CIAS film, ZnS film was deposited by chemical bath deposition method, and then Zn atoms diffused into the skin surface of the CIAS film during an annealing process. The skin surface of p-type CIAS can be transformed to a n-type CIAS. Therefore a pn-homojunction can be formed. Finally, the AZO and Ag electrode were deposited by sputtering and a pn-homojunction diode was fabricated. During the deposition of precursors, ZnS and AZO layer, shadow masks were used for forming a circle active area for the purpose of spreading current evenly. Scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction were used to observe the surface morphology, composition and phase identification of thin films, respectively. Photoluminescence measurement was to identify the bandgap of the CIAS film. Finally, the diodes were tested with forward bias. From the I-V curves, some devices showed obvious diode characteristics and a flash of lighting from the fabricated diodes can be observed without light pollution.
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Liao, Kuo-han, and 廖國涵. "Study of Sputtered P-N Homojunction Diodes of Polar n-Type on Nonpolar p-Type ZnO Thin Films." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/52994100626949376849.
Full textAbstract:
碩士國立中山大學
物理學系研究所
101
This thesis investigates thin-film P-N homojunction diodes made of c-textured ZnO deposited on a-oriented ZnO (a-ZnO) using r-Al2O3 as substrates. First, an a-ZnO epitaxial layer is grown on the r-oriented Al2O3 (r-Al2O3) substrate by RF sputtering. X-ray diffraction (XRD) was used to analyze the crystal structure and general qualities of the films via 2ɵ-ω, rocking curve, GIXRD and Φ- scans. Carrier concentration and mobility were determined by measuring the electrical and Hall resistivity using a Physical Property Measurement System (PPMS) made by Quantum Design, Inc., U.S.A. The charge carries of the epitaxial a-ZnO are p-type, while those of the textured c-ZnO are n-type. As ZnO tends to grow at room temperature (RT) along its c-axis without in-plane alignment, the n-layer was first grown at RT for 30s~120s, after which the growth temperature was raised to the desired levels while the deposition continued without interruption. The growth time at RT, final deposited temperature, and sputter-gun power were varied systematically in seeking optimal conditions for the diode performance. This includes the attempts, albeit unsuccessful, to make the c-textured films epitaxial. The textured nature of the n-type layer turns out to contain electrically leaky path, most likely along the boundaries among the single-crystalline domains. In order to incapacitate or remove these possible conducting channels, HF was used to etch the c-textured surface. The resulted devices were analyzed according to their I-V characteristics for samples obtained using the aforementioned material growth conditions and HF etching times.
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Liu, Fang-Cheng, and 劉芳成. "A Study on the ZnO-based Homojunction and ZnO/GaN Heterojunction Diodes with p-type Ag-ZnO Cosputtered film." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/645829.
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碩士國立虎尾科技大學
光電工程系光電與材料科技碩士班
106
In study,Ag dope ZnO films were prepared by RF magnetron co-sputtering system by p-type film, the heat treatment undoped ZnO film is activated, Changing the intermediate activation layer, adding barrier layer AlN-ZnO film double hetero-junction, improving the electronic hole limitation ability of the film, and adding aluminum nitride boundary layer to increase the ability of electronic limitation, so that the benefit of luminescence will be changed, is hall measurement of electrical properties and photoluminescence spectra to understand film stacking characteristics, the electrical characteristics can be found that the Ag dopede ZnO has a p-type conductive pattern. the double hetero-junction and the undoped ZnO film in the intermediate layer film show n-type conductive pattern, the photoluminescence spectra show that middle layer AlN-ZnO film double hetero-junction of the middle layer effectively inhibits the oxygen vacancy in the ZnO and increases the intensity of the luminescence in the short wavelength part, and the intensity of the short wavelength luminescence is obviously enhanced by the addition of the aluminum nitride layer.This study is made p-ZnO/n-ZnO、p-ZnO/DH/n-ZnO and p-ZnO/AlN/DH/n-ZnO homo- junction diode in sapphire substrate, In current-voltage characteristics, in middle layer AlN-ZnO film double hetero-junction, when the voltage is positive or negative 0.68V ,the current ratio is about 2.21, or confined aluminum nitride layer, when the voltage is positive or negative 1.15V ,the current ratio is about 5.59, Both have rectifying characteristics. Further study is made on the different bottom film n-GaN and p-GaN thin films as heterostructures, the n-GaN film is made for the structure bottom p-ZnO/n -GaN、p-ZnO/DH/ n-GaN and p-ZnO/AlN/DH/ n-GaN hetero-junction diode, it n-Gan crystal structure and electrical characteristics better than those of n-ZnO, In current-voltage characteristics, Both have very rectifying characteristics, study the p-Gan film is made for the structure bottom p-ZnO/p -GaN、p-ZnO/DH/ p-GaN and p-ZnO/AlN/DH/ p-GaN hetero-junction diode, from the electrical excitation spectrum and the band diagram, under voltage, the p-GaN film can provide a few holes to increase the electron hole recombination chance to produce luminescence, the addition of aluminum nitride confining layer prevents electrons from being confined to the activation layer of the intermediate layer, which enhances the single photoluminescence.
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Wang, Ding-Ce, and 王鼎策. "P-type Cuprous Oxide Thin Film Doped with Alkali Metal Ions for p–n Homojunction Cuprous Oxide Thin Film Solar Cells." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/66p99h.
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碩士國立東華大學
光電工程學系
107
In this study, p–n homojunction cuprous oxide thin film solar cells were grown on indium-doped tin-oxide (ITO) substrates by using the electrochemical deposition method. The electrolyte for depositing a p-type cuprous oxide thin film is prepared by using three different alkali metal hydroxides of lithium hydroxide, sodium hydroxide and potassium hydroxide. Desirable to improve the conductivity of the p-type cuprous oxide thin film by alkali metal ions doped. Further improve the efficiency of p–n homojunction cuprous oxide thin film solar cells. The p-type cuprous oxide thin film deposited by lithium hydroxide has lower lattice distortion and less lattice defects. Benefit from the improvement of the crystal structure of p-type cuprous oxide thin film, the p–n homojunction cuprous oxide thin film solar cells grown with lithium hydroxide has an optimum fill-factor of 0.34 and efficiency of 0.43%. Proof from experimental results, lithium ion doping can effectively improve the crystal structure of p-type cuprous oxide thin film, and improve the efficiency of p–n homojunction cuprous oxide thin film solar cells.
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El, Gohary Hassan Gad El Hak Mohamed. "Development of Low-Temperature Epitaxial Silicon Films and Application to Solar Cells." Thesis, 2010. http://hdl.handle.net/10012/5560.
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Solar photovoltaic has become one of the potential solutions for current energy needs and for combating greenhouse gas emissions. The photovoltaics (PV) industry is booming, with a yearly growth rate well in excess of 30% over the last decade. This explosive growth has been driven by market development programs to accelerate the deployment of sustainable energy options and rapidly increasing fossil fuel prices. Currently, the PV market is based on silicon wafer solar cells (thick cells of around 150–300 μm made of crystalline silicon). This technology, classified as the first-generation of photovoltaic cells. The second generation of photovoltaic materials is based on the introduction of thin film layers of semiconductor materials. Unfortunately, the conversion efficiency of the current PV systems is low despite the lower manufacturing costs. Nevertheless, to achieve highly efficient silicon solar cell devices, the development of new high quality materials in terms of structure and electrical properties is a must to overcome the issues related to amorphous silicon (a -Si:H) degradation. Meanwhile, to remain competitive with the conventional energy sources, cost must be taken into consideration. Moreover, novel approaches combined with conventional mature silicon solar cell technology can boost the conventional efficiency and break its maximum limits. In our approach, we set to achieve efficient, stable and affordable silicon solar cell devices by focusing on the development of a new device made of epitaxial films. This new device is developed using new epitaxial growth phosphorous and/or boron doped layers at low processing temperature using plasma enhanced chemical vapor deposition (PECVD). The junction between the phosphorous or boron-doped epitaxial film of the device is formed between the film and the p or n-type crystalline silicon (c-Si) substrate, giving rise to (n epi-Si/p c-Si device or p epi-Si/n c-Si device), respectively. Different processing conditions have been fully characterized and deployed for the fabrication of different silicon solar cells architectures. The high quality epitaxial film (up to 400 nm) was used as an emitter for an efficient stable homojunction solar cell. Extensive analysis of the developed fine structure material, using high resolution transmission electron microscope (HRTEM), showed that hydrogen played a crucial role in the epitaxial growth of highly phosphorous doped silicon films. The main processing parameters that influenced the quality of the structure were; radio frequency (RF) power density, the processing chamber pressure, the substrate temperature, the gas flow rate used for deposition of silicon films, and hydrogen dilution. The best result, in terms of structure and electrical properties, was achieved at intermediate hydrogen dilution (HD) regime between 91 and 92% under optimized deposition conditions of the rest of the processing parameters. The conductivity and the carrier mobility values are good indicators of the electrical quality of the silicon (Si) film and can be used to investigate the structural quality indirectly. The electrical conductivity analyses using spreading resistance profile (SRP), through the detection of active carriers inside the developed films, are presented in details for the developed epitaxial film under the optimized processing conditions. Measurements of the active phosphorous dopant revealed that, the film has a very high active carrier concentration of an average of 5.0 x1019 cm-3 with a maximum value of 6.9 x 1019 cm-3 at the interface between substrate and the epitaxial film. The observed higher concentration of electrically active P atoms compared to the total phosphorus concentration indicates that more than half of dopants become incorporated into substitutional positions. Highly doping efficiency ηd of more than 50 % was calculated from both secondary ion mass spectroscopy (SIMS) and SRP analysis. A variety of proposed structures were fabricated and characterized on planar, textured, and under different deposition temperatures. Detailed studies of the photovoltaic properties of the fabricated devices were carried out using epitaxial silicon films. The results of these studies confirmed that the measured open circuit voltage (Voc) of the device ranged between 575 and 580 mV with good fill factor (FF) values in the range of 74-76 %. We applied the rapid thermal process (RTP) for a very short time (60 s) at moderate temperature of 750oC to enhance the photovoltaic properties of the fabricated device. The following results were achieved, the values of Voc, and the short circuit current (Isc) were 598 mV and 27.5 mA respectively, with a fill factor value of up to 76 % leading to an efficiency of 12.5 %. Efficiency enhancement by 13.06 % was achieved over the reference cell which was prepared without using RTP. Another way to increase the efficiency of the fabricated device is to reduce the reflections from its polished substrate. This was achieved by utilizing the light trapping technique that transforms the reflective polished surface into a pyramidical texturing using alkaline solutions. Further enhancements of both Voc and Isc were achieved with values of 612 mV and 31mA respectively, and a fill factor of 76 % leading to an increase in the efficiency by up to 13.8 %. A noticeable efficiency enhancement by ~20 % over the reference cell is reported for the developed devices on the textured surfaces. Moreover, the efficiency of the fabricated epitaxial silicon solar cells can be boosted by the deployment of silicon nanocrystals (Si NCs) on the top surface of the fabricated devices. In the course of this PhD research we found a way to achieve this by depositing a thin layer of Si NCs, embedded in amorphous silicon matrix, on top of the epitaxial film. Structural analysis of the deposited Si NCs was performed. It is shown from the HRTEM analysis that the developed Si NCs, are randomly distributed, have a spherical shape with a radius of approximately 2.5 nm, and are 10-20 nm apart in the amorphous silicon matrix. Based on the size of the developed Si NCs, the optical band gap was found to be in the region of 1.8-2.2 eV. Due to the incorporation of Si NCs layer a noticeable enhancement in the Isc was reported.
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Chang, Chin-Ming, and 張晉銘. "Design and fabrication of p-Cu2O/n-Cu2O homojunction and p-Cu2O/n-Cu2O/n-ZnO heterojunction solar cells using electrochemical deposition method." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/8v8akd.
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碩士元智大學
化學工程與材料科學學系
106
In this study, Cu2O-based homojunction and heterojunction solar cell devices were designed, fabricated, and characterized. Several device structures, such as p-Cu2O/n-Cu2O homojunction and p-Cu2O/n-ZnO and p-Cu2O/n-Cu2O/n-ZnO heterojunction devices, were designed. The p-Cu2O and n-ZnO films were fabricated in different pH solution using electrochemical deposition processing. The ZnO layer was coated on top of the Cu2O layer to fabricate the heterojunction devices. Results showed that all the devices showed semiconductor diodes according to the I-V measurements. The heterojunction solar cell devices performed better, i.e. higher open circuit voltage (Voc) and short circuit current (Jsc), than the homojunction device. The p-Cu2O/n-Cu2O/n-ZnO device had the best solar cell performance among the devices. The characteristics of the heterojunction devices were influenced by the thermal treatment and the thickness of the Cu2O layers. The p-Cu2O/n-Cu2O/n-ZnO device demonstrated the apparently higher Voc (0.5 V) than the p-Cu2O/n-ZnO (0.2 V). This is because the p-Cu2O/n-Cu2O/n-ZnO device performance improved the junction contact by the presence of the n-ZnO layer between the p-Cu2O and n-ZnO layers.
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Marsi, Marino. "Interface effects at semiconductor homojunctions." 1992. http://catalog.hathitrust.org/api/volumes/oclc/28952926.html.
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YANG, KUN-WANG, and 楊坤旺. "Energy band structures of δ-doping GaAs homojunctions." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/76015940765183063307.
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Harada, Kentaro [Verfasser]. "Organic p-i-n homojunctions : fundamentals and applications / vorgelegt von Kentaro Harada." 2008. http://d-nb.info/990332357/34.
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Wang, Yau-Chyr, and 王瑤池. "Studies of the InGaAs/InAlAs Single Quantum Well, d-doped GaAs Homojunctions and the Interfacial Properties of Oxide-GaAs by Photoreflectance Spectroscopy." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/37905626407131706642.
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博士國立成功大學
物理學系
87
Photoreflectance (PR) spectra were measured from lattice-matched In0.53Ga0.47As/In0.52Al0.48As single quantum well structures (SQWs). The measurements allowed the observation of interband transitions from the heavy- and light-hole valence sub-bands to the conduction sub-bands. The transition energies measured from PR spectra agree with those theoretically calculated from the confined levels in the SQW. A built-in electric field in the sample was analyzed and located by sequential etching, measuring the series of PR spectra after each etching step. A blue shift in the extrema of the Franz-Keldysh oscillations (FKOs) of the PR spectra, caused by the phase shift of the PR spectra, was associated with each etching step. The phase spectra obtained from the PR spectra by Kramers-Kronig transformation was analyzed in terms of the two-ray model. This analysis was used to calculate the etching depth in each etching step, and thus led to the etching rate. The etching rate obtained from the phase shift analysis agrees with that measured by atomic force microscopy (AFM). Next, photoreflectance measurements have been performed on a d-doped GaAs homojunction. Two Franz-Keldysh oscillation features originating from two different regions (a buffer layer and a top layer) of the structure superimpose with each other in the photoreflectance spectrum. By properly selecting the reference phase, one of the features can be suppressed, thus enabling us to determine the electric fields from the two regions unambiguously. The electric field in the top layer is (3.5±0.2) ’105 V/cm, which is in good agreement with theoretical calculation. The electric field in the buffer layer is (1.2±0.1)’104 V/cm, which suggests the existence of the interface at the buffer/substrate interface. Finally, we studied the built-in electric fields and interfacial state densities (Dit) in a series of oxide-GaAs heterostructures fabricated by in-situ molecular beam epitaxy. The samples investigated were air-, Al2O3- Ga2Ox-, and Ga2O3(Gd2O3)-GaAs. We found that the built-in electric fields are 48, 44, and 38 kV/cm for air-, Al2O3- and Ga2Ox-GaAs samples, respectively. For the Ga2O3(Gd2O3)-GaAs sample, the built-in electric field is negligibly small, indicating a very low interfacial state density. Estimated by the low field limit criterion, Dit is less than 1’1011 cm-2eV-1. Our results are consistent with the previous data obtained using capacitance-voltage measurements in quasi-static/high frequency modes.