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Kayes, Brendan Melville Atwater H. A. Painter Oskar J. Atwater H. A. Lewis Nathan Saul. "Radial pn junction, wire array solar cells /." Diss., Pasadena, Calif. : Caltech, 2009. http://resolver.caltech.edu/CaltechETD:etd-09222008-173738.
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Limb, Jae Boum. "Design, fabrication and characterization of III-nitride PN junction devices." Diss., Available online, Georgia Institute of Technology, 2007, 2007. http://etd.gatech.edu/theses/available/etd-07022007-151130/.
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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008.William Doolittle, Committee Member ; Joy Laskar, Committee Member ; Russell Dupuis, Committee Chair ; David Citrin, Committee Member ; Srinivas Garimella, Committee Member.
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Hontgas, Christopher Hayden. "Investigation of PN Junction Delineation Resolution using Electron Beam Induced Current." Doctoral diss., University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3327.
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This dissertation will investigate electron beam induced current (EBIC) for determining semiconductor material and device parameters. While previous experimental work on PN junction delineation using EBIC with the scanning electron microscope has resulted in resolution to approximately 10 nm, theoretical study shows the potential use of EBIC for higher resolution (nanometer) PN junction and FET channel length delineation using the transmission electron microscope. Theoretical arguments using computer simulations of electron beam generation volume, collection probability and EBIC were performed and are presented for the purpose of determining EBIC use in a 300 keV transmission electron microscope (TEM) for PN junction depth determination. Measured results indicate that by measuring thin semiconductor samples with high surface recombination velocity and by using a narrow, high-energy electron beam in the STEM mode of a transmission electron microscope, nanometer resolution may be possible. The practical and experimental limits of beam energy and semiconducting material thermal damage will be discussed.Ph.D.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering PhD
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Ska-Hiish, Manuel Dave Hokororo. "A performance analysis of planar and radial pn junction based photovoltaic solar cells." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45418.
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In this thesis, the performance of both planar and radial pn junction based photovoltaic
solar cells are examined for a broad range of materials. The materials
considered include silicon, gallium arsenide, germaniun, indium nitride, and gallium
nitride. The photovoltaic solar cell performance model of Kayes et al. [B.M.
Kayes, H.A. Atwater, and N.S. Lewis, Journal of Applied Physics, volume 97, pp.
14302-1-11, 2005], is employed for the purposes of this analysis. Three solar cell
performance metrics, evaluated using the et al., model are considered in this analysis:
(1) the short-circuit current density, (2) the open-circuit voltage, and (3) the
efficiency. The results suggest that while planar pn junction based photovoltaic solar
cells are sensitive to trapping concentration levels, the radial pn junction based
photovoltaic solar cells are relatively insensitive to trapping concentrations. This
suggests that in certain cases, such as when there are materials with high concentration
of traps, radial pn junction based photovoltaic solar cell offer inherent
advantages over their planar counterparts.
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Klimíček, Jaromír. "Šumová diagnostika PN přechodu usměrňovacích diod." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217439.
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The thesis deals with the design of the measurement installation, which is intended for the microplasma noise measurements. This noise is being generated in the defective parts of the PN junction. The goal of this work is to design the measurement installation and to realize the fully functional workbench for the analogical noise related measurements and to determine the transfer function of the measurement installation. Main part of the work is to choose proper parameters for the measuring devices and to design the software intended for the automated measurements. Consequently, we have to process the measured waveforms of the microplasma noise, to determine the dependency of the noise on the signal magnitude and to calculate the power spectral noise density. Finally, we have to determine the transfer function of the measurement installation and to design the inversion filter.
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Brasseur, Paul. "Mach Zehnder interferometry and coherent manipulation of the valley in a graphene PN junction." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASP012.
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L’optique quantique électronique, i.e. la réalisation de l’analogue électronique d’expériences d’optique quantique, constitue un champ de recherche récent, en plein développement, et offrant des perspectives intéressantes pour l’informatique quantique. Dans ce cadre, l’un des enjeux est la réalisation de bits quantiques en utilisant des états électroniques, ainsi que la formation d’états électroniques intriqués, éléments de bases pour réaliser des calculs quantiques plus élaborés. Les expériences menées jusqu’à présent dans des hétérostructures semi-conductrices de GaAs/AlGaAs ont mis en évidence la possibilité d’encoder l’information dans la charge ou le spin d’un électron, mais la décohérence importante de ces systèmes induit une grande fragilité de ces états quantiques, qui ne peuvent exister qu’en-dessous de 100mK et pour des tensions résiduelles inférieures à 40μV. Cette fragilité rend difficile la fabrication d’états intriqués, et est limitante pour le développement de calculs quantiques complexes. En 2005, la découverte d’un matériau novateur, le graphène, a ouvert de nouvelles perspectives avec la prédiction d’une cohérence de phase plus grande, et, d’autre part, l’existence en plus du spin d’un nouveau degré de liberté, la vallée, donnant accès à de nouvelles possibilités pour encoder l’information. Dans un premier temps, ce travail de thèse porte sur la manipulation cohérente de la vallée, nécessaire à la réalisation d’un bit quantique de vallée dans le graphène. Pour cela est utilisée, en régime Hall quantique, une jonction pn, formée à l’aide de grilles déposées sur un échantillon de graphène encapsulé dans du nitrure de Bohr. Afin d’obtenir un contrôle électrostatique sur la polarisation en vallée des électrons incidents, des grilles locales ont été déposées, à l’intersection de la jonction pn avec le bord physique du graphène. En alliant ce contrôle électrostatique à celui de la phase Aharanov-Bohm, il nous est possible de manipuler de manière cohérente la vallée d’un électron sur l’ensemble de la sphère de Bloch représentant la polarisation en vallée. Dans la suite, la cohérence des états quantiques formés est étudiée grâce à un interféromètre de Mach Zehnder, via l’observation de la dépendance des interférences en fonction de la tension appliquée sur les électrons incidents, et de la température du système. Les états quantiques obtenus sont exceptionnellement résistants, ils persistent au-delà de 1.5K et de 1mV, soit à des énergies près de 20 fois supérieures à celles observées dans le GaAs/AlGaAs.Puis, ce manuscrit décrit l’étude de la longueur de cohérence, correspondant à la distance sur laquelle un électron peut se propager en gardant sa cohérence de phase, ce qui n’avait encore jamais été mesuré dans le graphène. Pour ce faire, la dépendance des interférences vis-à-vis de la température a été mesurée sur trois jonctions pn de longueurs différentes. Une longueur de cohérence a ainsi été extraite pour les deux régimes de décohérence observés ; dont une record, pour le régime à basses températures, de plus de 374μm à 20mK. Pour finir, est investigué un des mécanismes causant la décohérence dans le système : les ondes de spin, se propageant lorsque le cœur du graphène est magnétique. Ainsi, au cours de ce projet, nous avons mis en évidence la possibilité d’encoder de l’information dans la vallée, ouvrant la voie vers un nouveau domaine : la vallée-tronique. D’autre part, la cohérence du système est exceptionnelle, permettant d’envisager la réalisation d’états intriqués grâce à une géométrie de double Mach Zehnder. Cela offre des perspectives prometteuses du point de vue de l’informatique quantique, mais aussi d’un point de vue fondamental avec la possibilité de démontrer pour la première fois, avec des fermions, la validité des prédictions de l’interprétation de Copenhague de la physique quantique dans le cadre du paradoxe EPRElectron quantum optics, i.e. the realization of the electronic analogue of quantum optics experiments, represents a developing and recent research field, offering interesting perspectives for quantum computing. In this context, one of the main stakes is the achievement of quantum bits using electronic states, as well as the creation of entangled electronic states, which are the building blocks to achieve complex quantum computations. Up to now, the experiments carried out in semi-conducting GaAs/AlGaAs heterostructures exhibited the possibility to encode information in the charge or the spin of an electron, but strong decoherence in these systems implies a great weakness of these quantum states, which survives only below temperatures of 100mK and electrical biases of 40μV. This fragility makes it difficult to achieve entangled states and limits the development of complex quantum computations. In 2005, the discovery of a novel material, graphene, opened new prospects with on one hand the prediction of a larger phase coherence, and on the other hand the existence, in addition to the spin, of a new degree of freedom, named the valley, giving access to new possibilities to encode information. In a first part, this PhD work deals with the coherent manipulation of the valley, which is necessary to achieve a valley quantum bit in graphene. For this aim, we used, in the quantum Hall regime, a graphene pn junction, formed thanks to gates deposited on top of a stack composed of a graphene sheet encapsulated in Boron nitride crystals. In order to obtain an electrostatic control of the valley polarization of incoming electrons, we deposited local gates at the intersections between the pn junction and the graphene physical edge. Associating this electrostatic control to a tuning of the Aharanov-Bohm phase, we can coherently manipulate the valley of an electron over the whole states described by a valley Bloch sphere. In what follows, the coherence of the quantum states is investigated thanks to Mach Zehnder interferometry, by measuring the interferences dependence on the chemical potential of incoming electrons and on the temperature of the system. The quantum states formed are exceptionally steady, they persist up to 1.5K and 1mV, in other words at energies 20 times higher than what was observed in GaAs/AlGaAs.Then, the manuscript describes the study of the coherence length, i.e. the distance on which an electron can propagate while keeping its phase coherence, which has never been measured in the quantum Hall regime in graphene. To that end, the interferences dependence on the temperature was measured in three pn junctions of different lengths. By doing so, two coherence lengths, corresponding to two different regimes of decoherence, were extracted; in the regime occurring at low temperature, a record value of 374μm at 20mK was obtained.Finally, we investigated one of the mechanisms of decoherence in our system: spin waves, propagating in the graphene bulk when it is magnetized. During this project, we have shown the possibility to encode information in the valley and to manipulate coherently this degree of freedom, paving the way towards a new domain: the valleytronics. Furthermore, the coherence of the system is exceptional, enabling to envision the achievement of entangled electronic states by using a double Mach Zehnder interferometer geometry. This opens promising prospects for quantum computing, but also for fundamental purposes, with the possibility to demonstrate, for the first time with fermions, the validity of the Copenhagen interpretation of quantum physics within the EPR paradox framework
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Derishev, Anton. "Měření kapacity vysokonapěťových přechodů PN." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2015. http://www.nusl.cz/ntk/nusl-221152.
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The work deals with the capacitance measurement of high-voltage PN junctions. The work is divided into theoretical and practical parts. The theoretical part presents insight into the fundamental properties of PN junctions and methods for measuring of the capacitance of PN junctions, primarily by C-V measurement. In the practical part, several kinds of measuring circuits are introduced and a suitable method of measurement is found. The calculations of basic parameters - the width of the base and resistivity are presented and discussed. The results were compared with the values obtained by calculation from the technological parameters of the junction.
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El-Amin, Ammaarah Haleemah. "Investigation of Semitransparent Cu2O/ZnO Based Heterostructure Diodes for Memory and Related Applications." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1388761525.
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Chavez, Ruben [Verfasser], and Roland [Akademischer Betreuer] Schmechel. "High Temperature Thermoelectric Device Concept Using Large Area PN Junction / Ruben Chavez. Betreuer: Roland Schmechel." Duisburg, 2015. http://d-nb.info/107979350X/34.
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Al, Imam Shahriar. "Simulation of a 2D pn junction in silicon thin film incorporating quantum transport for carriers." Thesis, Connect to online version, 2006. http://proquest.umi.com/pqdweb?did=1251871411&sid=3&Fmt=2&clientId=10306&RQT=309&VName=PQD.
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Gama, Richard. "Průzkum trhu výkonových polovodičových součástek." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-318410.
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In this thesis I will evaluate few discrete devices and their differences in structure, static and switching characteristics and also some structurall and manufacturing principles. After that I will follow up with their integration into power modules , where I will also aim on construction solutions and trends. These power moduls are today delivered as „stack“ or „system“, where for optimization and highest achievable efficiency of the whole unit the integration of protection, drive and cooloing stage is incorporated. Cooling and drive of some devices will be subject of a separate chapter. Also some of novel materials, which are very promissing, will be introduced. They show improvemnet in electrical and thermal properties. They have potential to replace the currently dominant Silicon in the near future.
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Krčál, Ondřej. "Využití záření emitovaného z lokálních oblastí PN přechodu pro diagnostiku solárních článků." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217452.
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The microplasma discharges in the PN junction local defect micro-regions are as a rule, accompanied by the emission of light. This radiation from solar cell PN junctions was measured by means of a optical fibre connected to the optical input of a photomultiplier. By inching the fibre by means of computercontrolled X-Y plotter above the cell surface a 2-D image of the irradiation local regions has been created. It is seen that a cell of a superficial area of 100 square cm contains a large number of defects, which depends on applied reverse voltage. This method can be a convenient tool for study and diagnostics of optoelectronic devices.
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Raška, Michal. "Diagnostika PN přechodu křemíkových vysokonapěťových usměrňovacích diod pomocí šumu mikroplazmatu." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-233496.
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The doctoral thesis deals with diagnostics of local defects in PN junctions and brings new information about microplasma noise behaviour and its usage for the temperature changes detection inside PN junctions. Defects in PN junctions are the source of microplasma noise. There were deviations observed in microplasma noise from the common known rectangle shape pulses during the measurements. These deviations were correlated with the temperature change directly in the defect area and in the defect area surroundings. Generation and recombination coefficients are commonly thought to be constant. However, these coefficients were observed to be not stable with time and this effect is explained in this work. The doctoral thesis then focuses on the PN junction parameters determination in the case when it is not possible to define unambiguously whether it is abrupt or linearly graded PN junction. The most significant parameters which are to be determined are barrier capacity, diffusion voltage and depleted area width in dependence on the voltage. The correlation between local avalanche discharge in PN junction and negative differential resistance appearance on VA characteristics of reverse-biased diode was qualitatively verified. The last important point in the work is computer modelling of temperature behaviour in the defect area and its surroundings during local avalanche breakdown. Thus the method of real diodes heating area parameters determination was introduced.
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Issa, Fatima. "Réalisation de détecteurs de neutrons en carbure de silicium." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4303/document.
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Les détecteurs de radiations nucléaires sont des outils importants dans de nombreux domaines tels que dans les réacteurs nucléaires, la sécurité nationale, mais ils sont également primordiaux dans des applications médicales. Les progrès récents dans la technologie des semi-conducteurs permettent la réalisation de détecteurs très efficaces et quasi-insonores qui permettent la détection de différents types de radiations nucléaires. Le carbure de silicium (SiC) est une bande semi-conductrice large, grâce à sa conductivité thermique élevée et à une résistance élevée aux rayonnements, il est adapté pour les environnements difficiles où peuvent exister des flux élevés de température et de rayonnement. Le but du projet européen (I_SMART) est ainsi de prouver la fiabilité de nouvelles méthodes de réalisation de détecteurs de radiations nucléaires et d'étudier leur performance dans différents types d'irradiation (neutrons rapides et thermiques) et à différentes températures. Différentes méthodes ont été utilisées pour réaliser les détecteurs de rayonnement SiC. Par exemple l'implantation d'ions de bore a été utilisé pour créer la couche de conversion de neutrons soit dans le contact métallique ou directement en SiC. Les détecteurs fabriqués ont été testés dans le réacteur nucléaire BR1, mettant en lumière la présence de neutrons thermiques. En outre, ces détecteurs détectent des neutrons rapides sous n’importe quelle température. En outre, les détecteurs utilisés montrent leur stabilité sous différents flux de neutrons qui indiquent la fiabilité de ces nouveaux modes de réalisation de détecteurs de rayonnement qui pourraient remplacer ceux utilisés actuellementNuclear radiation detectors are important tools in many fields such as in nuclear reactors, homeland security and medical applications. Recent advances in semiconductor technology allow construction of highly efficient low noise detectors for different nuclear radiations. Silicon carbide (SiC) is a wide band gap semiconductor with a high thermal conductivity and high radiation resistance. It is suitable for a harsh environment where high temperatures and radiation fluxes may exist. In the framework of the European project (I_SMART) the purpose of this work is to demonstrate the reliability of new methods of realizing nuclear radiation detectors and to study their performance under different types of irradiation (fast and thermal neutrons) and at elevated temperatures. Different methods have been used to realize SiC based-radiation detectors. For instance boron ion implantation has been used to create the neutron converter layer either in the metallic contact or directly in the SiC. The fabricated detectors have been tested in the BR1 nuclear reactor revealing the thermal neutron detection and the feasibility of gamma discrimination from thermal neutrons using one single detector. Such detectors are sensitive to fast neutrons with a stable response under elevated temperatures (up to 150 °C). Furthermore, the studied detectors show stability under different neutron fluxes, indicating a reliability of such new methods of realizing radiation detectors which could replace those of the current state of the art
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Lipr, Tomáš. "Měření kvantové účinnosti optoelektronických prvků a návrh laboratorního měřícího systému." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219353.
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This thesis deals with the issue of quantum efficiency measurement of optoelectronic devices. The physical nature of silicon solar cells is explained here. In addition, the quantum efficiency as a concept is introduced. There is also discussed the influence of a solar cell semiconductor structure on the quantum efficiency itself. Furthermore, the thesis is focused on the design of an experimental set-up for automated measurement and data acquisition. The final realization of the step motor control unit is described in detail. It includes local and/or remote operations, design and development motivation. The next chapter is dedicated to analysis of the Matlab source code for remote operation, data acquisition and presentation. The final part of the thesis gives attention to experiments with real structures, not only the solar cells. The obtained results of analyzed measurements are presented at the conclusion.
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Major, Jan. "Počítačové modelování MOSFET tranzistoru." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219148.
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Work is focused on computer modeling of PN junction and MOSFET transistor in the program COMSOL Multiphysics and in program TiberCAD. The text is discussed on the drift and diffusion in semiconductors. Also shown is a method of modeling the PN junction and MOSFET transistor in the programs and compare models.
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Avelas, Resende Joao. "Copper-based p-type semiconducting oxides : from materials to devices." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAI072/document.
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L'absence d'oxydes semi-conducteurs de type p de haute performance retarde le développement de d’électronique transparente et du photovoltaïque à base d’oxydes. Dans le groupe des composés semi-conducteurs, les oxydes à base de cuivre présentent des caractéristiques électriques, optiques et de fabrication prometteuses qui établissent cette famille de matériaux comme bien adaptés aux applications semi-conductrices de type p. Dans ce travail, nous nous concentrons sur la croissance de films minces d’une part de Cu2O dopée par des cations et d’autre part de CuCrO2, visant à améliorer leurs propriétés optiques et électriques. De plus, nous avons mis en œuvre ces films d'oxyde dans des dispositifs de jonction pn tels que des cellules solaires et des photodétecteurs UV.Dans le travail sur Cu2O, nous avons réalisé l'incorporation de magnésium jusqu'à 17% dans des films minces par dépôt chimique en phase vapeur assisté par aérosol, entraînant des changements de morphologie. La résistivité électrique a été réduite jusqu’à des valeurs de 6,6 ohm.cm, en raison de l'augmentation de la densité de porteur de-charges jusqu'à 10^18 cm-3. L'incorporation du magnésium a en outre eu un impact sur la stabilité de la phase Cu2O. En effet la transformation du Cu2O en CuO en conditions oxydantes est considérablement retardée par la présence de Mg dans les films, en raison de l'inhibition de la formation d’un type particulier de lacune de cuivre (split vacancy). L'intégration dans les jonctions pn a été réalisée avec succès en utilisant uniquement des voies de dépôt chimique en phase vapeur, en combinaison avec le ZnO de type n. Néanmoins, l'application de Cu2O dopé au Mg dans les cellules solaires présente un effet photovoltaïc très faible, loin des meilleures valeurs de l’état de l’art.Dans le travail sur CuCrO2, nous démontrons la première fabrication d'hétérostructures de nanofils en configuration cœur/coquille ZnO/CuCrO2 utilisant des techniques de dépôt chimique adaptées pour des grandes surface, à faible coût, facilement implémentées à des températures modérées et leur intégration dans des photodétecteurs UV auto-alimentés. Une coquille conforme de CuCrO2 avec la phase de delafossite et avec une uniformité élevée a été élaborée par un dépôt chimique en phase vapeur assisté par aérosol sur un réseau de nanofils ZnO alignés verticalement, obtenu par dépôt par bain chimique. Les hétérostructures ZnO/CuCrO2 coeur-coquille présentent un comportement rectificatif significatif, avec un ratio de rectification maximal de 5500 à ± 1V, ce qui est bien meilleur que les dispositifs 2D similaires rapportés dans la littérature, ainsi qu'une absorption élevée supérieure à 85% dans la région UV. Lorsqu'ils sont appliqués en tant que photodétecteurs UV auto-alimentés, les hétérojonctions optimisées présentent une réponse maximale de 187 μA / W sous une polarisation nulle à 374 nm ainsi qu'une sélectivité élevée avec un ratio de rejet entre l’UV-et le visible (374-550 nm) de 68 sous irradiance de 100 mW/cm2The lack of a successful p-type semiconductor oxides delays the future implementation of transparent electronics and oxide-based photovoltaic devices. In the group semiconducting compounds, copper-based oxides present promising electrical, optical and manufacturing features that establish this family of materials suitable for p-type semiconductor applications. In this work, we focused on the growth of cation doped Cu2O and intrinsic CuCrO2 thin films, aiming for enhancements of their optical and electrical response. Furthermore, we implemented these oxide films into pn junction devices, such as solar cells and UV photodetectors.In the work on Cu2O, we achieved the incorporation of magnesium up to 17% in thin films by aerosol-assisted chemical vapor deposition, resulting in morphology changes. Electrical resistivity was reduced down to values as low as 6.6 ohm.cm, due to the increase of charge-carrier density up to 10^18 cm-3. The incorporation of magnesium had additionally an impact on the stability of the Cu2O phase. The transformation of Cu2O into CuO under oxidizing conditions is significantly postponed by the presence of Mg in the films, due to the inhibition of copper split vacancies formation. The integration into pn junctions was successfully achieved using only chemical vapor deposition routes, in combination with n-type ZnO. Nevertheless, the application of Mg-doped Cu2O in solar cells present a meager photovoltaic performance, far from the state-of-the-art reports.In the work on CuCrO2, we demonstrate the first fabrication of ZnO/CuCrO2 core-shell nanowire heterostructures using low-cost, surface scalable, easily implemented chemical deposition techniques at moderate temperatures, and their integration into self-powered UV photodetectors. A conformal CuCrO2 shell with the delafossite phase and with high uniformity is formed by aerosol-assisted chemical vapor deposition over an array of vertically aligned ZnO nanowires grown by chemical bath deposition. The ZnO/CuCrO2 core-shell nanowire heterostructures present a significant rectifying behavior, with a maximum rectification ratio of 5500 at ±1V, which is much better than similar 2D devices, as well as a high absorption above 85% in the UV region. When applied as self-powered UV photodetectors, the optimized heterojunctions exhibit a maximum responsivity of 187 µA/W under zero bias at 374 nm as well as a high selectivity with a UV-to-visible (374-550 nm) rejection ratio of 68 under an irradiance of 100 mW/cm2
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Darebný, Tomáš. "Návrh fotovoltaického systému rodinného domu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-319625.
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Basic knowledge of photovoltaic energy transformation, devices and materials, used in photovoltaic are summarized in this master's thesis. The main goal of this thesis is orientation in the photovoltaic systems used these days and explain advantages and disadvantages of these systems during the design phase.
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Golda, Martin. "Polovodičové struktury, metoda nábojového sběru." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220953.
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This thesis treats about semiconducting silicon structures. It describes the characteristics of the element and creation of P and N type of semiconductor and discusses about different types of faults in the crystal lattice. It deals with the description of methods for monitoring faults in semiconductor ie. determining the properties of semiconductors via EBIC, EBIV and CC methods, which are used for analysis of semiconductor devices and materials. Determining the properties of silicon components is being done by generation of charge carriers in the sample loaded in chamber of the scanning electron microscope by high energy electrons. Bellow the sample surface is being generated an electric charge which is being collected by probes. Using this data obtained by EBIC and CC were evaluated diffusion length and lifetime of electrons.
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Hills, Romilly D. Y. "Physical properties of graphene nano-devices." Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/17993.
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In this doctoral thesis the two dimensional material graphene has been studied in depth with particular respect to Zener tunnelling devices. From the hexagonal structure the Hamiltonian at a Dirac point was derived with the option of including an energy gap. This Hamiltonian was then used to obtain the tunnelling properties of various graphene nano-devices; the devices studied include Zener tunnelling potential barriers such as single and double graphene potential steps. A form of the Landauer formalism was obtained for graphene devices. Combined with the scattering properties of potential barriers the current and conductance was found for a wide range of graphene nano-devices. These results were then compared to recently obtained experimental results for graphene nano-ribbons, showing many similarities between nano-ribbons and infinite sheet graphene. The methods studied were then applied to materials which have been shown to possess three dimensional Dirac cones known as topological insulators. In the case of Cd3As2 the Dirac cone is asymmetrical with respect to the z-direction, the effect of this asymmetry has been discussed with comparison to the symmetrical case.
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Davidová, Lenka. "Diagnostika polovodičových materiálů metodou EBIC." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-319289.
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Master´s thesis is focused on diagnostics of semiconductor materials by EBIC method (measuring of currents induced beam), determination of the lifetime of minority carriers, or their diffusion length. The theoretical part is aimed at the principle of scanning electron microscopy, the characteristic properties of the microscope and the signals generated by the interaction of the primary electron beam with the sample. The thesis describes a structure of semiconducting silicon, band models, types of lattice defects and doped of semiconductor structures. After that it is described the theory of calculation of the diffusion length of minority carriers in semiconductors of type N and P. The aim of the experiment part of the thesis is to measure the properties of the semiconductor structure by EBIC and determination of diffusion length and lifetime of minority charge carriers based on the measured data The aim of the experiment part of the thesis is to measure the properties of the semiconductor structure by EBIC and determination of diffusion length and lifetime of minority charge carriers on the basis of the measured data.
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Kadlec, Michal. "Vliv magnetického pole na vlastnosti fotovoltaických článků." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220104.
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This thesis describes the issue of PN junction of photovoltaic cells, photovoltaic effect physics, basic materials used in photovoltaic and their properties, important for the area of photovoltaic. It deals with the problems of magnetism focused on electromagnetic fields. Experimental facility for measuring the influence of magnetic field on the solar cells through the Helmholtz coils was constructed. This work also dealing with the influence of magnetic radiation on photovoltaic cells and the influence of electromagnetic waves on the volt-ampere characteristics of the photovoltaic cell.
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Ibaceta, Jaña Josefa Fernanda. "Thermal instabilities of charge carrier transport in solar cells based on GaAs PN Junctions." Tesis, Universidad de Chile, 2017. http://repositorio.uchile.cl/handle/2250/145405.
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Magíster en Ciencias de la Ingeniería, Mención Mecánica.
Ingeniera Civil MecánicaDentro de los factores que afectan negativamente una celda solar fotovoltaica se destaca la temperatura. Ya sea por imperfecciones del material o a condiciones de operación no uniformes, es posible que se concentre calor en una zona debido a la disminución de la resistencia local y su consecuente aumento de corriente eléctrica. Estas zonas de concentración de calor pueden estabilizarse, generando gradualmente degradación de la celda, disminución de su vida útil y eficiencia. En caso contrario, puede ocurrir un fenómeno de descontrol térmico que resulta catastrófico para la celda, inhabilitando su correcto funcionamiento. Estudios en módulos de película delgada revelan que esta condición ocurre incluso cuando la radiación está uniformemente distribuida y con ello, el perfil de temperatura inicial es constante. La evolución temporal, bajo radiación, induce zonas de calor que incrementan exponencialmente la temperatura, contrayendo su área; por otra parte, la temperatura de las zonas más alejadas disminuye simultáneamente mientras disipan pequeñas corrientes. Para evitar este fenómeno se pueden escalar propiedades del dispositivo, como aumentar la conductividad térmica y disminuir el espesor. Actualmente, estos análisis se realizan a partir de modelos numéricos y analíticos basados en el comportamiento de diodos y mediciones experimentales del perfil de temperatura en la capa superficial de la celda y en la juntura. El propósito de esta Tesis es determinar criterios de estabilidad electro-térmico que pueden ser utilizados para evitar el descontrol de temperatura a partir de aplicar un análisis a un modelo hidrodinámico de mayor complejidad que uno basado en diodos; más aún, considerar un estado fuera del equilibro entre la temperatura de la red y los portadores de carga. Se determinó que la inestabilidad ocurre en la juntura PN y depende fuertemente la temperatura de la juntura en los bordes. Además, aumentar la temperatura de los portadores, disminuir el largo y aumentar el voltaje aplicado pueden estabilizar el sistema, aumentando el tiempo en que el sistema duplica su temperatura.
Este trabajo ha sido parcialmente financiado por CONICYT-PCHA/Magíster Nacional/2016 - 22160729
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Škarvada, Pavel. "Lokální optické a elektrické charakteristiky optoelektronických součástek." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-233561.
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Solar energy conversion, miniaturization of semiconductor devices and associated lifetime, reliability and efficiency of devices are the basic premise of this work. This work is focused on the study of optoelectronic devices especially solar cells and its nondestructive diagnostic. Solar cells are advantageous for study mainly because the pn junction is located near the surface and contains a lot of inhomogeneities. It has been difficult until recently to investigate their local physical (electrical and optical) parameters due to the size of inhomogeneities. Behavior of inhomogeneities can be well understood with knowledge of its local properties. Establishment of measurement workplace, that satisfies requirements for measurement of local emission and optically induced current measurement, allows us detection and localization of inhomogeneities with spatial resolution more or less 100 nm. The core of thesis is characterization of imperfection using nondestructive techniques in the macroscopic region but primarily in microscopic region using scanning probe microscopy. Integral parts of the work are characterization techniques for photoelectrical devices, microscopic techniques and data processing. Scanning near-field optical microscope is used for the purpose of microscopic characterization such as topography, local optical, photoelectrical and electrooptical properties of structures in high spatial resolution. Locally induced current technique, current voltage characteristics, emission from reversed bias pn junction measurement including its thermal dependence are used for samples investigation in macroscopical region. It is possible to localize defects and structure inhomogeneity using mentioned techniques. Localised defects are consequently analyzed for composition and measured using electron microscopy. Specific outputs of work are classification of photoelectric devices defects and specification of nondestructive characterization techniques used for defect detection. Experimental characterization techniques are described together with defects measurement procedures. The key output is the catalog of serious defects which was detected. Particular defects of samples are shown including describe of its properties and physical meaning.
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Lavayssiere, Maylis. "Electrical and chemical mapping of silicon pn junctions using energy-filtered X-ray PhotoElectron Emission Microscopy." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00765630.
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Ce mémoire de thèse traite de l'étude de jonctions pn silicium planaires, réalisées par épitaxie localisée, avec un nouveau type de microscopie à émission de photoélectrons (XPEEM) filtré en énergie. L'objectif est d'améliorer notre compréhension des facteurs influençant l'imagerie XPEEM de jonctions modèles avec une perspective à plus long terme d'application de cette technique aux cas réels. Sur les trois types de jonction réalisées présentant des champs électriques variables P+/P, N+/P, P+/N), nous avons d'abord mis en oeuvre un procédé de passivation en trois étapes afin de se rapprocher de conditions en bandes plates en surface. Ce procédé nous a permis d'étudier la position des niveaux électroniques de part et d'autre des jonctions grâce à une imagerie en XPEEM spectroscopique avec électrons secondaires (travail de sortie local), électrons de coeur Si 2p et bande de valence, avec à la fois avec des sources X de laboratoire et le rayonnement synchrotron. Un mécanisme de contraste des images en électrons de coeur dû à la toute première couche atomique de surface a été montré. Ensuite, nous avons mis en évidence le rôle du champ électrique au niveau de la zone de déplétion des jonctions qui décale la position apparente de cette dernière dans l'image XPEEM. Nous avons comparé les résultats expérimentaux avec des simulations (logiciel SIMION) afin d'estimer son influence sur les conditions d'imagerie. Enfin, nous avons étudié l'impact de la technique d'imagerie en champ sombre sur la localisation de la jonction réelle au niveau de la surface de l'échantillon.
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Lavayssière, Maylis. "Electrical and chemical mapping of silicon pn junctions using energy-filtered X-ray PhotoElectron Mission Microscopy." Thesis, Grenoble, 2011. http://www.theses.fr/2011GRENT024.
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Ce mémoire de thèse traite de l'étude de jonctions pn silicium planaires, réalisées par épitaxie localisée, avec un nouveau type de microscopie à émission de photoélectrons (XPEEM) filtré en énergie. L'objectif est d'améliorer notre compréhension des facteurs influençant l'imagerie XPEEM de jonctions modèles avec une perspective à plus long terme d'application de cette technique aux cas réels.Sur les trois types de jonction réalisées présentant des champs électriques variables (P+/P, N+/P, P+/N), nous avons d'abord mis en œuvre un procédé de passivation en trois étapes afin de se rapprocher de conditions en bandes plates en surface. Ce procédé nous a permis d'étudier la position des niveaux électroniques de part et d'autre des jonctions grâce à une imagerie en XPEEM spectroscopique avec électrons secondaires (travail de sortie local), électrons de cœur Si 2p et bande de valence, avec à la fois avec des sources X de laboratoire et le rayonnement synchrotron. Un mécanisme de contraste des images en électrons de cœur dû à la toute première couche atomique de surface a été montré. Ensuite, nous avons mis en évidence le rôle du champ électrique au niveau de la zone de déplétion des jonctions qui décale la position apparente de cette dernière dans l'image XPEEM. Nous avons comparé les résultats expérimentaux avec des simulations (logiciel SIMION) afin d'estimer son influence sur les conditions d'imagerie. Enfin, nous avons étudié l'impact de la technique d'imagerie en champ sombre sur la localisation de la jonction réelle au niveau de la surface de l'échantillonThis thesis addresses the problem of imaging of model systems planar silicon pn junctions, fabricated by localized epitaxy, using the novel energy-filtered X-ray PhotoElectron Emission Microscope (XPEEM). The objective is to improve the understanding of the phenomena influencing the XPEEM images of the junctions, with as long-term perspective, a possible application of this method in a complementary way to existing techniques of 2D dopant mapping.The studies were carried out over three types of junction realized to this purpose and presenting variable electrical field (P+/P, N+/P, P+/N). We firstly developed and optimized a passivation protocol in three-steps which yielded a surface close to flat band conditions. This process allowed us to deduce band alignments as a function of doping level and type on both side of the junction thanks to spectroscopic XPEEM imaging of secondary electrons (to determine local work function), Si 2p core-level and valence band with both laboratory photon sources and synchrotron radiation. Contrast in core-level imaging due to the first atomic layer of the surface was also shown.Then, we highlighted the role of the lateral electric field across the depletion zone of a pn junction which shifts the apparent position of the latter in PEEM imaging. We compared experimental results and simulations performed with SIMION software to estimate the influence of pn junctions on PEEM imaging. Dark field imaging of the junction was also simulated. Comparison with the experimental results showed that it can be used to localize the real junction
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Wolf, Daniel. "Elektronen-Holographische Tomographie zur 3D-Abbildung von elektrostatischen Potentialen in Nanostrukturen." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-65125.
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Die Aufklärung der grundlegenden Struktur-Eigenschaft-Beziehung von Materialen auf der (Sub-)Nanometerskala benötigt eine leistungsfähige Transmissionselektronenmikroskopie. Dabei spielen insbesondere die durch die Nanostruktur hervorgerufenen intrinsischen elektrischen und magnetischen Feldverteilungen eine entscheidende Rolle. Die Elektronen-Holographische Tomographie (EHT), d.h. die Kombination von off-axis Elektronenholographie (EH) und Elektronentomographie (ET), bietet einen einzigartigen Zugang zu dieser Information, weil sie die quantitative 3D-Abbildung elektrostatischer Potentiale und magnetostatischer Vektorfelder bei einer Auflösung von wenigen (5-10) Nanometern ermöglicht. Für die Rekonstruktion des 3D-Potentials erfolgt zunächst die Aufzeichnung einer Kippserie von Hologrammen im Elektronenmikroskop. Durch die anschließende Rekonstruktion der Objektwelle aus jedem Hologramm liegt eine Amplituden- und eine Phasenkippserie vor. Die Phasenkippserie wird schließlich zur tomographischen 3D-Rekonstruktion des elektrostatischen Potentials verwendet. Im Rahmen dieser Arbeit wurde die EHT von einer manuell aufwendigen zu einer weitestgehend automatisierten Methode entwickelt. Die Automatisierung beinhaltet die Entwicklung des ersten Softwarepaketes zur computergestützten Aufzeichnung einer holographischen Kippserie (THOMAS). Verglichen mit rein manueller Vorgehensweise verkürzt sich mit THOMAS die Dauer für die Aufnahme einer holographischen Kippserie, bestehend aus Objekt- und Leerhologrammen, auf weniger als ein Drittel. Mittlerweile beträgt die Aufnahmezeit im Mittel etwa 2-3 Stunden. Auch die holographische Rekonstruktion und zugehörige Operationen zur Entfernung von Artefakten in den Phasenbildern ist durch entsprechende Prozeduren, welche für eine gesamte Kippserie in einem Schritt anwendbar sind, automatisiert. Zudem ermöglichen erst spezielle selbstentwickelte Ausrichtungsmethoden die exakte Verschiebungskorrektur von Kippserien der hier untersuchten stabförmigen Objekte (Nanodrähte, FIB-präparierte Nadeln). Für die tomographische Rekonstruktion wurde in dieser Arbeit die Simultane Iterative Rekonstruktionstechnik (SIRT) zur W-SIRT weiterentwickelt. In der W-SIRT wird statt einer Einfachen eine Gewichtete Rückprojektion bei jeder Iteration verwendet, was eine bessere Konvergenz der W-SIRT gegenüber der SIRT zur Folge hat. Wie in anderen ET-Techniken auch, ist in der EHT für die Rekonstruktion des dreidimensionalen Tomogramms meist nur aus Projektionen innerhalb eines begrenzten Winkelbereichs möglich. Dies führt in den Tomogrammen zu einem sogenannten Missing Wedge, welcher neben dem Verlust von Au ösung auch Artefakte verursacht. Daher wird eine Methode vorgestellt, wie sich das Problem des Missing Wedge bei geeigneten Objekten durch Ausnutzung von Symmetrien entschärfen lässt. Das mittels EHT rekonstruierte 3D-Potential gibt Aufschluss über äußere (Morphologie) und innere Objektstruktur, sowie über das Mittlere Innere Potential (MIP) des Nanoobjektes. Dies wird am Beispiel von epitaktisch gewachsenen Nanodrähten (nanowires, NWs) aus GaAs und AlGaAs demonstriert. Anhand entsprechender Isopotentialflächen im 3D-Potential lässt sich die 3D-Morphologie studieren: Die Facetten an der Oberfläche der NWs erlauben Rückschlüsse über die dreidimensionale kristalline Struktur. Des Weiteren zeigt das rekonstruierte 3D-Potential eines AlGaAs/GaAs-Nanodrahtes deutlich dessen Kern/Schale-Struktur, da sich GaAs-Kern und AlGaAs-Schale bezüglich des MIP um 0.61 V unterscheiden. Im Falle dotierter Halbleiterstrukturen mit pn-Übergang (z.B. Transistoren) bietet die mittels EHT rekonstruierte Potentialverteilung auch Zugang zur Diffusionsspannung am pn-Übergang. Diese Größe kann ohne Projektions- und Oberflächeneffekte (dead layer) im Innern der Probe gemessen und in 3D analysiert werden. Für drei nadelförmig mittels FIB präparierte Proben (Nadeln) werden die Diffusionsspannungen bestimmt: Die Messungen ergeben für zwei Silizium-Nadeln jeweils 1.0 V und 0.5 V, sowie für eine Germanium-Nadel 0.4 V. Im Falle der GaAs- und AlGaAs-Nanodrähte reduziert der Missing Wedge die Genauigkeit der mittels EHT gewonnenen 3D-Potentiale merklich, insbesondere bezüglich der MIP-Bestimmung. Dagegen stimmen die Potentiale der Germanium und Silizium-Nadeln exzellent mit theoretischen Werten überein, wenn der Missing Wedge durch Ausnutzung der Objektsymmetrie behoben wirdRevealing the essential structure-property relation of materials on a (sub-)nanometer scale requires a powerful Transmission Electron Microscopy (TEM). In this context, the intrinsic electrostatic and magnetic fields, which are related to the materials nano structure, play a crucial role. Electron-holographic tomography (EHT), that is, the combination of off-axis electron holography (EH) with electron tomography (ET), provides an unique access to this information, because it allows the quantitative 3D mapping of electrostatic potentials and magnetostatic vector fields with a resolution of a few (5-10) nanometers. The reconstruction of the 3D potential starts with the acquisition of a hologram tilt series in the electron microscope. The subsequent reconstruction of the electron object wave from each hologram yields a tilt series in both amplitude and phase images. Finally, the phase tilt series is used for the tomographic reconstruction of the 3D potential. In this work, EHT has been developed from a manual and time-consuming approach to a widely automated method. The automation includes the development of the first software package for computer-controlled acquisition of holographic tilt series (THOMAS), a prerequisite for efficient data collection. Using THOMAS, the acquisition time for a holographic tilt series, consisting of object and reference holograms, is reduced by more than a factor of three, compared to the previous, completely manual approaches. Meanwhile, the acquisition takes 2-3 hours on average. In addition, the holographic reconstruction and corresponding methods for removal of artefacts in the phase images have been automated, now including one-step procedures for complete tilt series. Furthermore, specific self-developed alignment routines facilitate the precise correction of displacements within the tilt series of the rod-shaped samples, which are investigated here (e.g. nanowires, FIB needles). For tomographic reconstruction, a W-SIRT algorithm based on a standard simultaneous iterative reconstruction technique (SIRT) has been developed. Within the W-SIRT, a weighted back-projection instead of a simple back-projection is used. This yields a better convergence of the W-SIRT compared to the SIRT. In most cases in EHT (likewise in other ET techniques), the reconstruction of the three-dimensional tomogram is only feasible from projections covering a limited tilt range. This leads to a so-called missing wedge in the tomogram, which causes not only a lower resolution but also artefacts. Therefore, a method is presented, how to solve the missing wedge problem for suitable objects by exploiting symmetries. The 3D potential offers the outer (morphology) and inner structure, as well as the mean inner potential (MIP) of the nano object. This is shown by means of EHT on epitaxially grown nanowires (NWs) of GaAs and AlGaAs. The 3D morphology is studied using the corresponding iso-surfaces of the 3D potential: The facets on the nanowires surface allow conclusions about the crystalline structure. Moreover, the reconstructed 3D potential of a AlGaAs/GaAs NW clearly shows its core/shell structure due to the MIP difference between GaAs and AlGaAs of 0.61 V. In case of doped semiconductor structures with pn-junctions (e.g. transistors) the potential distribution, reconstructed by EHT, also provides access to the built-in voltage across the pn-junction. The built-in voltage can be analyzed in 3D and measured without projection and surface effects (e.g. dead layers) within the sample. The measurements in three needle-shaped specimens, prepared by FIB, yield for two silicon needles 1.0 V and 0.5 V, and for a germanium needle 0.4 V. In case of the GaAs and AlGaAs nanowires the missing wedge reduces the accuracy of the reconstructed 3D potentials significantly, in particular in terms of MIP determination. However, the potentials of the silicon and germanium needles are in excellent agreement with theoretical values, when the object symmetry is exploited to fill-up the missing wedge
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Husák, Marek. "Využití šumové diagnostiky k analýze vlastností solárních článků." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-217922.
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The master’s thesis deals with the noise diagnostic in the solar cells. Describes the main kinds of noises. The samples were quality and reliability screened using noise reliability indicators. The samples were surveyed by measuring the I-V characteristics, the noise spectral density as a function of forward voltage and frequency. It was calculated the noise spectral density as a function of forward current.
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Way, Austin J. "Fabrication of a-Si and a-InGaN Photovoltaics by Plasma Sputtering." Ohio University Honors Tutorial College / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1398270155.
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Hwang, Chiao-Kai, and 黃昭凱. "Nano-PN Junction." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/49743516774851788827.
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碩士國立交通大學
理學院IC製程化學產業專班
96
“Diode” has so far been widely applied in the Very-large-scale integration (VLSI). What is more, the theorem and characteristics of its device also lay a solid foundation for the device of semiconductor. Nowadays, the feature size of semiconductor has been downsized into a nano-scale which makes the existing theories insufficient to explain both its effect and property. However, if well utilized, its novel property will lead into a brand-new application level. The Solar cell made of silicon substrate has currently been in an extensive application; nevertheless, its conversion efficiency is far disappointing when compared to solar cell made of heterojunction GaAs. The major explanation lays on the fact that the property of Si belongs to material of Non-direct energy band. This special property helps Si absorb more wavelength than GaAs; however, it also causes comparatively stronger Saturation Current in which the leakage effects are increased and the whole conversion efficiency is decreased accordingly. Hence, the research focus of this dissertation is aiming at proposing a method which hopefully will improve the property of saturation current of si-based. Through E-Beam Lithography, this experiment is intended to build a device of PN Junction diode made of Si material in a nano scale. Besides, the experiment also probes into whether the saturation current of Silicon substrate can be alleviated effectively out of its special structure and, what is more, in comparison with those traditional PN Junction diodes by observing two different PN Junction diodes to understand if their electrical characteristics will be different.
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Kayes, Brendan Melville. "Radial pn Junction, Wire Array Solar Cells." Thesis, 2009. https://thesis.library.caltech.edu/3702/1/Brendan_Kayes_Thesis.pdf.
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Radial pn junctions are potentially of interest in photovoltaics as a way to decouple light absorption from minority carrier collection. In a traditional planar design these occur in the same dimension, and this sets a lower limit on absorber material quality, as cells must both be thick enough to effectively absorb the solar spectrum while also having minority-carrier diffusion lengths long enough to allow for efficient collection of the photo-generated carriers. Therefore, highly efficient photovoltaic devices currently require highly pure materials and expensive processing techniques, while low cost devices generally operate at relatively low efficiency.
The radial pn junction design sets the direction of light absorption perpendicular to the direction of minority-carrier transport, allowing the cell to be thick enough for effective light absorption, while also providing a short pathway for carrier collection. This is achieved by increasing the junction area, in order to decrease the path length any photogenerated minority carrier must travel, to be less than its minority carrier diffusion length. Realizing this geometry in an array of semiconducting wires, by for example depositing a single-crystalline inorganic semiconducting absorber layer at high deposition rates from the gas phase by the vapor-liquid-solid (VLS) mechanism, allows for a "bottom up" approach to device fabrication, which can in principle dramatically reduce the materials costs associated with a cell.
This thesis explores the potential of this design, first theoretically and computationally, and then by exploring the growth of structures with the proposed morphology via methods with the potential for low cost, and finally by the experimental characterization of cells.
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Chen, Hong-Ruei, and 陳宏睿. "Fabrication and characteristics of diamond PN junction device." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/xgr2qk.
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碩士國立中山大學
機械與機電工程學系研究所
97
This work has employed the Micro-wave Plasma enhanced Chemical Vapor Deposition (MPCVD) method to fabricate diamond PN junction device. The n+ <111> orientation single-crystal silicon has used as substrates. P-type diamond layer is doped with B(OCH3)3 and the N-type diamond layer is doped with ammonia. The surface structure of diamond film has been observed by scanning electron microscope; and the device rectification property of a PN junction has measured by current-voltage characteristic. The carrier density and mobility of diamond films have been analyzed by Hall measurement. Furthermore, the Cathodoluminescence (CL) spectroscopy showed the defect spectra in diamond PN junction. The N-type diamond film and P-type diamond film have deposited at temperature of 800 ℃, for 30 minutes and 90 minutes, respectively. The process CVD has performed in the same chamber continually. A I-V curve of sample showed the set on positive voltage 0.5 V and the reverse breakdown voltage of 6 V. Further, CL results revealed a peak at 285 nm (4.4 eV), which represents the CVD diamond band and the other one is at 500 nm (2.5 eV), which stands for donor-acceptor recombination from defect in these diamond films.
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Huang, Chi-Lin, and 黃棋林. "Fabrication of PN junction micro-ring electro-optic modulator." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/79461479576578340094.
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Liao, Kuei-Tsun, and 廖貴村. "Gold Doped High Speed Switching PN Junction Diode Device." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/27944265946261170301.
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碩士國立交通大學
電子研究所
83
The task of this thesis is to obtain a higher trap concentration to reduce the switching time in diodes. Deep level Transient spectroscopy (DLTS) is employed to study the electric active deep levels and the trap concentration. In additional, Secondary Ion Mass Spectroscopy (SIMS) and spread resistance measurement are also performed to study the distribution of diffused Au element in Si and the variation of conductivity in Si, respectively. Two energy levels are observed. An acceptor and a donor level are located at Ec-0.56 eV and Ev+0.35eV,respectively. It is found that the concentration of deep levels due to Au diffusion increases with increasing temperature and duration. Furthermore, the switching time decreases with increasing temperature and duration. Based on these results, diodes with shorter time (10nsec) can be obtained by a long duration Au diffusion at higher temperatures. The gold distribution is uniform except the region near the Si surface. The distribution profile of Au shows an accumulation region near the Si surface. This Au accumulation is ion-pairing or gold-phosphorus complexes related.
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Yang, Che-Yun, and 楊哲昀. "The study of SiCN PN Junction and SiCN/Si Hetero-junction High Temperature UV Detector." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/99690683524398739573.
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碩士國立成功大學
微電子工程研究所碩博士班
93
This thesis reports the growth and analysis of SiCN films prepared by rapid-thermal chemical vapor deposition (RTCVD). During the growing process, we use two kinds of gas (Propane and MS) for the resource of carbon. Based on XRD, FTIR, AFM, the structure of grown SiCN film is crystalline and embedded in CNx matrix. Additionally, the films with Propane as carbon source possess smoother morphology than the films with MS. Next, we use SiCN film to prepare SiCN/SI hetero-junction and SiCN/SiCN PN junction UV detectors. Experimental results show the ratio of photo current to dark current under irradiation of UV(254nm) for n-SiCN/p-Si detector is better than that for p-SiCN/n-Si. On the other hand, if an intrinsic layer was added in the structure i.e., n-SiCN/i-SiCN/p-Si, the photo/dark current ratio can be promoted 200% in magnitude. The current ratio decreased with increase of operation temperature. However, up to 150℃ current ratio of all samples can also have 2~3 and work normally. Moreover, the SiCN/SiCN samples possess current ratio more than ten thousand, thus evidences the developed SiCN films are good enough for preparation of high temperature UV detectors.
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Lin, Yung-chin, and 林詠進. "Breakdown simulation of a spherical PN junction in cylindrical coordinates." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/79624541975897000626.
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碩士國立中央大學
電機工程研究所碩士在職專班
100
In this thesis, the breakdown phenomenon of a spherical PN junction is studied in 3D cylindrical coordinates. We analyze the shift of I-V curve, potential deviation and compare the deviation between 3D cylindrical coordinates and 3D Cartesian coordinates. We develop the trapezoid 3D cube in cylindrical coordinates. The simulation speed and accuracy in 3D cylindrical coordinates is better than that in Cartesian coordinates. We also verify the simulation result with the theory. Then, we change different parameters such as the radius of a p-n junction, doping concentration and grid points to see the dependence of breakdown voltage on these parameters. Finally, we study how to find a better grid design and get a better simulation result.
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Fang, Hong-Chih, and 枋泓志. "3D PN Diode Equation and Device Simulation with spherical Junction." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/23572300766126286763.
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碩士國立中央大學
電機工程研究所
100
In this thesis, we try to derive the analytical equations of the potential, the electric field, and the depletion width in a three-dimensional spherical pn junction. The analytical equations for spherical pn junction is more complex than that for 1D pn junction. However, the depletion width can be obtained by a simple calculation. We compare the analytical results with the results from 3D numerical simulation. With these analytical equations, we can quickly investigate the dependence of the depletion width, the maximum electric field, and the breakdown voltage on the radius of a spherical pn junction. Similarly, the dependence of the depletion width, the maximum electric field, and the breakdown voltage on the doping of a spherical pn junction can be obtained quickly.
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Tso, Yu-sheng, and 左裕昇. "Analysis and simulation cylindrical coordinates of curved PN junction properties." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/54857792560891176434.
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碩士國立中央大學
電機工程研究所
98
In this paper, we use the cylindrical coordinates to substitute Cartesian coordinates. Because of the symmetry and certainty we use the cylindrical coordinates to analyze and simulate the curved PN junction. First, we analyze and simulate the forward I-V curve and reverse I-V curve based on the trapezoid cell. Second, we discuss the breakdown voltage in reversed bias with different diffusion radius. Finally, comparisons between two coordinates show that the cylindrical coordinates is better because of its symmetry in the curved PN junction.
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Ying-Wen, Huang. "Study of new type spin transistors based on silicon pn junction." 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0016-0109200613405076.
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Li, Kun-Shu, and 李坤樹. "Optical and Electrical Properties of Silicon Based MILC PN Junction Diode." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/66335600129001260230.
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碩士大葉大學
電機工程學系
95
Recently, polycrystalline silicon (Poly-Si) has received increasing attention because of its wide range application, such as Thin Film Transistor (TFT) for liquid crystal display, solar cell and image sensors. The growth methods of Poly-Si include (1) Solid Phase Crystallization (SPC) (2) Excimer Laser Annealing (ELA) (3) Metal-Induced Crystallization (MIC). However, SPC method have high growth temperature (above 700℃), resulting in fused quartz or silicon substrate is needed, which is high cost. The ELA method is expensive and cannot mass production due to laser annealing. In this experiment, we deposited the hydrogenated amorphous silicon (a-Si:H) films by Plasma-enhanced chemical vapor deposition (PECVD) system; then, the metal-induced lateral crystallization (MILC) of hydrogenated amorphous silicon (a-Si:H) thin films was processed having various thicknesses of nickel (Ni) films (10~25nm) at 550℃.The n-type Poly-Si film was grown on p-Si subatrate by using MILC method; then, a p/n junction solar cell was fabricated. It was found that the Poly-Si films prepared by MILC method have a nano- grain size of about 20~ 65 nm. The MILC method was treated by using RTA system at 550℃ for 6 hours. The optimal crystallization was achieved in the samples having 20 nm thick Ni films. The ratio of photo-to-dark-current ratio was 23, and the measured conversion efficiency of the solar cell was 6.1% by AM1.
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Huang, Ying-Wen, and 黃瀛文. "Study of new type spin transistors based on silicon pn junction." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/04862063106269512899.
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博士國立清華大學
材料科學工程學系
94
This work has focused on the study of two new type silicon-base spin transistors. These two new type spin transistors are combined either pseudo spin-valve or magnetic tunneling junction with a p-n junction to form a spin-valve transistor (SVT) or magnetic tunneling transistor (MTT). For SVT, the emitter current (IE) changed from 1uA to 0.968uA at different magnetically states in the common collector (CC) circuitry with an emitter bias (VE) and a base bias (VB) at room temperature (RT). At the same states the base currents (IB) changed form 29.3 uA to 333 nA which gave a magnetocurrent (MC) of 8600% and a transfer ratio (α) of 3E−2. In CC configuration with a base resistor (RB) and an VE of 5.12 V at 77 K gives a large collector current (IC) of more than 95.5 mA and the change is more than 3400% with a α of 2.59E−3. At RT, these changes go down to 98.3 mA and 55.3%, respectively, and the α rises to 5.98E−3. The MC of the collector in a SVT has been studied with both experiments and computer calculations. For MTT, IB change of roughly 6300% has been observed in the CC configuration with an VE and a VB at RT. In CC configuration with VE and RB at RT, the MC of the collector can be stabilized roughly above 40% at VE = 1.25±025V with α of 2.88% in the CC circuitry. IC can be more than 4 uA at the magnetic parallel state. The magnetoimpedance (MZ) effect of the SVT was investigated at RT in the frequency ranged from 100 Hz to 15 MHz. The SVT can be regarded as a complex combination of resistors, inductors, and capacitors; all these components exhibit magnetic hysteresis. It is due to the frequency dependent behavior that R does not reach a minimum at the resonant frequency (fr). The frequency dependences of MZ and MX ratios cross zero at fx = 6.5 MHz and at fr=3.65 MHz, respectively. The shape of magnetoreactance loop is reversed to the magnetoresistance loop. The MZ loop also reverses shape and sign after crossing fx.
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Su, Huan-Kuan, and 蘇桓寬. "Fabrication and measurement of asymmetric PN junction silicon microring electro-optical modulator." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/51920429730206810721.
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Lee, Chih-Hsuan, and 李志軒. "A small-angle method for breakdown simulation in 2D circular PN junction." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/56749945772404208926.
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碩士國立中央大學
電機工程研究所碩士在職專班
99
In this thesis, the major discussion is the small angle method in PN junction. The small angle model comes from 90° junction type of a full circular junction. For breakdown analysis, the result from the small angle method is the same as that from the original 90°junction method. The small angle method is verified for its validity by the test with different radii and different angles. The simulation result is not accepted if the angle is too small and the number of square meshes is insufficient. Finally, the comparison on the breakdown voltage and the CPU time between two methods shows that the small angle method is excellent in reducing the CPU time without increasing the programming complexity.
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Li, Zong Han, and 李宗翰. "Effects of antimony dopants on optical and electrical properties of InGaP PN junction." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/76530864349203657664.
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碩士長庚大學
光電工程研究所
102
In this paper ,it is different flow ratio (Sb/V=0, 3.25E-4, 6.5E-4, 13E-4) of antimony-doped gallium indium phosphide were grown on GaAs substrate by metal organic chemical vapor deposition (MOCVD) to research properties of GaInP. The experiments focused on optical measurements and electrical measurements . We used X-ray diffraction(XRD), Secondary Ion Mass Spectrometry(SIMS), Current-Voltage curve measurements(I-V), Capacitors-Frequency curve measurements(C-F), Capacitance-Voltage curve measurements (C-V), photoluminescence(PL) and Transmission Electron Microscopy(TEM) to analyze our samples. Comparison of concentrations between un-doped and doped samples in the four groups were made. Details will be discussed in the thesis.
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CHO, PO-HAN, and 卓伯翰. "Geometric Model and Simulation Verification of Cylindrical PN Junction for Electric Field Characteristics." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/r73j5r.
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碩士國立中央大學
電機工程學系
107
In this thesis, we will use a simple geometric model to derive the analytic formulas of electric field and use the developed trapezoidal module to simulate the characteristics for cylindrical PN junction. The equivalent circuit of each trapezoid is composed of two triangular modules. Through these analytic formulas and simulated characteristic results, we can observe the characteristics of electric field and some detailed phenomena. In addition, we also have more understanding of the plane junction and the cylindrical junction. It is worth noting that the electric field of the plane junction is linear and the electric field of the cylindrical junction is superlinear. Since the built-in voltages of the two are the same, the cylindrical junction has a larger maximum electric field, which also results in a lower breakdown voltage.
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Hsieh, Po-chine, and 謝伯健. "Impact-Ionization Parameter Extraction by PN Junction Simulation with a Decoupled or Coupled Method." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/40172482055027785045.
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碩士國立中央大學
電機工程研究所
100
This thesis reports the extraction of impact ionization for the silicon material. We design a 2-D device simulator which includes the impact ionization model to simulate the avalanche breakdown. At first, we use p-n diode to discuss the impact generation current with different doping concentration in p-n diode. Secondly, we introduce two methods for impact ionization extraction. One is the decoupled method. This method is used to find the intercept and slope for the electron impact ionization parameters if the hole impact ionization parameters are given. We obtain four I-V curves from 4 guessed parameters, and compare the 4 I-V curves with the measured I-V curve. The 4 guessed parameters forms a square in the 2D searching space. By moving the square and comparing the I-V curves, the intercept and the slope parameters can be obtained. Similarly, the hole impact ionization parameters can be obtained. The other method is the coupled method. The coupled method is used to find electron and hole impact ionization parameters simultaneously with 4 unknown variables. Compared with the extraction method in one fixed electric field, this method is more efficient and accurate because the intercept and the slope are valid for a wide range of electric filed.
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Sun, Cherng-En, and 孫晟恩. "Electrical Characteristics for Flash Memory with pn-Junction Diode as the Charge-Trapping Layer." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/99464254432375680727.
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Fang, Yu-pin, and 方昱斌. "Formation of pn Junction by Sputtering Epitaxy Method and its Application to Photovoltaic Devices." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/74927671283538345513.
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碩士國立臺灣科技大學
電子工程系
98
Continuous Si homoepitaxy were realized by using DC magnetron sputtering and its application for solar cell devices in this article. The good quality of epitaxial Si films can be obtained at the conditions of substrate temperature was 220℃, discharge power was 100 W and thickness was 350 nm. The characteristic of epi-layer are lifetime of 59.1 μs and recombination velocity of 287 cm/sec. The n+-p junction solar cells were fabricated with the optimum processed parameter. At the thickness of 650 nm, the conversion efficiency is 8.53%, fill factor is 0.64, open-circuit voltage is 0.51 V, and current density is 18.3 mA/cm2.
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Li, Cheng-Hua, and 李政樺. "The Effects of Heat Treatments on Zinc Nitride Thin Films and the PN Junction Characterization." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/v9x45a.
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碩士國立中山大學
機械與機電工程學系研究所
97
There are many intensive researches for zinc compounds due to their wide band gaps and potential applications in visible and UV optoelectronic technologies. Zinc nitride is a n-type semiconductor material having a direct band gap, and is not widely studied. Previous papers reported that zinc nitride is a n-type semiconductor having low resistivity and high electron mobility. Its band gap varies from 1.23 eV to 3.2 eV depending on the process condition. In this work, we successfully fabricated zinc nitride p-n junction by heat treatment on zinc nitride films. The threshold voltage of p-n junction is about 1 V. The Zinc nitride films were prepared by reactive RF magnetron sputtering. The as-grown zinc nitride thin film is a n-type material. It is found that the film treated at 300℃ for 3 hours can be changed to a p-type material. The zinc nitride has a very low resistance (2.2×10-2 Ω-cm) and high carrier concentration (3.88×1019 cm-3) after the heat treatment. The optical band gap of zinc nitride was determined as a direct band gap varying from 1.1 eV to 1.6 eV according to the temperature of heat treatment. The zinc nitride was successfully prepared with various electrical characteristics and band gaps by controlling the temperature of heat treatment.
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Lin, Hsin-An, and 林信安. "Breakdown simulation of a spherical PN junction with a small-angle method in 3D rectangular coordinates." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/36525755852071436134.
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碩士國立中央大學
電機工程研究所碩士在職專班
100
In this thesis, the major discussion is to improve the computer calculation time with the original simulation program in 3D rectangular coordinates. The small-angle method is used to divide the original silicon component into two parts. One is silicon region and the other is silicon-oxide region. The silicon region is inside the small-angle region, and we use the added silicon-oxide region to meet the simulation in 3D rectangular coordinates. Using this method, the simulation time is reduced to only one percent of the original. Further, the developed method is verified for its validity by the test with different parameters. So the small-angle method in 3D rectangular coordinates is workable and valuable.