Dissertations / Theses on the topic 'Passivation'
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1
Gheorghita, Ligia. "Passivation kinetics at semiconductor interfaces." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0016/NQ46347.pdf.
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Davenport, Alison Jean. "Passivation of amorphous and polycrystalline metals." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328717.
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Osorio, Ruy Sebastian Bonilla. "Surface passivation for silicon solar cells." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:46ebd390-8c47-4e4b-8c26-e843e8c12cc4.
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Passivation of silicon surfaces remains a critical factor in achieving high conversion efficiency in solar cells, particularly in future generations of rear contact cells -the best performing cell geometry to date. In this thesis, passivation is characterised as either intrinsic or extrinsic, depending on the origin of the chemical and field effect passivation components in dielectric layers. Extrinsic passivation, obtained after film deposition or growth, has been shown to improve significantly the passivation quality of dielectric films. Record passivation has been achieved leading to surface recombination velocities below 1.5 cm/s for 1 Ωcm n-type silicon covered with thermal oxide, and 0.15 cm/s in the same material covered with a thermal SiO2/PECVD SiNx double layer. Extrinsic field effect passivation, achieved by means of corona charge and/or ionic species, has been shown to decrease by 3 to 10 times the amount of carrier recombination at a silicon surface. A new parametrisation of interface charge, and electron and hole recombination velocities in a Shockley-Read-Hall extended formalism has been used to model accurately silicon surface recombination without the need to incorporate a term relating to space-charge or surface damage recombination. Such a term is unrealistic in the case of an oxide/silicon interface. A new method to produce extrinsic field effect passivation has been developed in which charge is introduced into dielectric films at high temperature and then permanently quenched in place by cooling to room temperature. This approach was investigated using charge due to one or more of the following species: ions produced by corona discharge, Na+, K+, Cs+, Mg2+ and Ca2+. It was implemented on both single SiO2 and double SiO2/SiNx dielectric layers which were then measured for periods of up to two years. The decay of the passivation was very slow and time constants of the order of 10,000 days were inferred for two systems: 1) corona-charge-embedded into oxide grown on textured FZ-Si, and 2) potassium ions driven into an oxide on planar FZ-Si. The extrinsic field effect passivation methods developed in this work allow more flexibility in the combined optimisation of the optical properties and the chemical passivation properties of dielectric films on semiconductors. Increases in cell Voc, Jsc and η parameters have been observed in simulations and obtained experimentally when extrinsic field effect passivation is applied to the front surface of silicon solar cells. The extrinsic passivation reported here thus represents a major advancement in controlled and stable passivation of silicon surfaces, and shows great potential as a scalable and cost effective passivation technology for solar cells.
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Chatterjee, Basab. "Hydrogen passivation of heteroepitaxial indium phosphide /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487947908403973.
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Jagannathan, Hemanth. "Semiconductor nanowires : synthesis, passivation, and devices /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Adhikari, Hemant. "Growth and passivation of germanium nanowires /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Fehrman, Stephen A. "Passivation of polymer light-emitting diodes." Click here to view, 2009. http://digitalcommons.calpoly.edu/eesp/19/.
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Thesis (B.S.)--California Polytechnic State University, 2009.Project advisor: David Braun. Title from PDF title page; viewed on Jan. 28, 2010. Includes bibliographical references. Also available on microfiche.
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Lenglet, Sergueï. "Bisimulations dans les calculs avec passivation." Phd thesis, Grenoble, 2010. http://www.theses.fr/2010GRENM002.
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Les calculs de processus représentent les systèmes concurrents par des processus qui s'exécutent en parallèle et s'échangent des messages. Les calculs avec passivation dispose d'un opérateur spécial qui permet de stopper un processus en cours d'exécution. Le processus suspendu peut ensuite être modifié ou transmis avant d'être réactivé. La passivation rend possible la modélisation de défaillances et d'opérations de reconfiguration dynamique. Nous nous intéressons aux équivalences comportementales dans ces calculs. Le comportement d'un processus est donné par un système de transitions étiquetées, qui exhibe les interactions d'un processus avec son environnement. Des relations, appelées bisimilarités, permettent ensuite d'identifier les processus qui ont le même comportement en comparant leurs interactions. Les bisimilarités définies jusqu'ici dans les calculs avec passivation restent trop complexes pour être utilisée en pratique. En outre il n'existe pas de bisimilarité correcte et complète dans le cas faible, c'est-à-dire lorsque les actions internes aux processus ne sont pas observables. Nous étudions ces deux problèmes dans cette thèse. Nous montrons d'abord qu'il est possible de définir une bisimilarité simple à manipuler pour un calcul avec passivation mais sans restriction. En revanche, nous donnons des contre-exemples qui laissent penser qu'il n'est pas possible de faire de même dans les calculs avec passivation et restriction. Nous définissons également un nouveau type de système de transitions étiquetées, qui permet de caractériser la congruence barbue dans le cas faible. Nous appliquons notre technique à différents calculs dont le KellIn process calculi, concurrent and interacting systems are modelled by processes that run in parallel and exchange messages. Calculi with passivation features a special operator that allows to stop a process at any time of its execution; the suspended process may then be modified or forwarded before being reactivated. Passivation is useful to model failures or dynamic reconfiguration phenomena. We are interested in behavioral equivalences in these calculi. The behavior of a process is given by a labelled transition system, which exhibits the interactions of a process with its environment. Bisimilarities then relate processes by comparing their interactions. Until now, the bisimilarities defined in calculi with passivation are too complex to be used in practice. Furthermore, there is no characterization of barbed congruence in the weak case, where internal actions from processes are not observable. We deal with this two issues in this document. We first define an easy to use bisimilarity in a calculus with passivation but without restriction. However, we give counter-examples which suggest that it is not possible to to do so in calculi with passivation and restriction. We also define a new kind of labelled transition system, which allows the characterization of the barbed congruence even in the weak case. We apply our technique to different calculi, including the Kell
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Lenglet, Sergueï. "Bisimulations dans les calculs avec passivation." Phd thesis, Grenoble, 2010. http://tel.archives-ouvertes.fr/tel-00447857.
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Les calculs de processus représentent les systèmes concurrents par des processus qui s'exécutent en parallèle et s'échangent des messages. Les calculs avec passivation dispose d'un opérateur spécial qui permet de stopper un processus en cours d'exécution. Le processus suspendu peut ensuite être modifié ou transmis avant d'être réactivé. La passivation rend possible la modélisation de défaillances et d'opérations de reconfiguration dynamique. Nous nous intéressons aux équivalences comportementales dans ces calculs. Le comportement d'un processus est donné par un système de transitions étiquetées, qui exhibe les interactions d'un processus avec son environnement. Des relations, appelées bisimilarités, permettent ensuite d'identifier les processus qui ont le même comportement en comparant leurs interactions. Les bisimilarités définies jusqu'ici dans les calculs avec passivation restent trop complexes pour être utilisée en pratique. En outre il n'existe pas de bisimilarité correcte et complète dans le cas faible, c'est-à-dire lorsque les actions internes aux processus ne sont pas observables. Nous étudions ces deux problèmes dans cette thèse. Nous montrons d'abord qu'il est possible de définir une bisimilarité simple à manipuler pour un calcul avec passivation mais sans restriction. En revanche, nous donnons des contre-exemples qui laissent penser qu'il n'est pas possible de faire de même dans les calculs avec passivation et restriction. Nous définissons également un nouveau type de système de transitions étiquetées, qui permet de caractériser la congruence barbue dans le cas faible. Nous appliquons notre technique à différents calculs dont le Kell.
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Wolborski, Maciej. "Termination and passivation of Silicon Carbide Devices." Licentiate thesis, KTH, Microelectronics and Information Technology, IMIT, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-439.
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Silicon carbide rectifiers are commercially available since 2001, and MESFET switches are expected to enter the market within a year. Moreover, three inch SiC wafers can be purchased nowadays without critical defects for the device performance and four inch substrate wafers are announced for the year 2005. Despite this tremendous development in SiC technology, the reliability issues like device degradation or high channel mobility still remain to be solved.
This thesis focuses on SiC surface passivation and termination, a topic which is very important for the utilisation of the full potential of this semiconductor. Three dielectrics with high dielectric constants, Al2O3, AlN and TiO2, were deposited on SiC with different techniques. The structural and electrical properties of the dielectrics were measured and the best insulating layers were then deposited on fully processed and well characterised 1.2 kV 4H SiC PiN diodes. For the best Al2O3 layers, the leakage current was reduced to half its value and the breakdown voltage was extended by 0.5 kV, reaching 1.6 kV, compared to non passivated devices.
As important as the proper choice of dielectric material is a proper surface preparation prior to deposition of the insulator. In the thesis two surface treatments were tested, a standard HF termination used in silicon technology and an exposure to UV light from a mercury lamp. The second technique is highly interesting since a substantial improvement was observed when UV light was used prior to the dielectric deposition. Moreover, UV light stabilized the surface and reduced the leakage current by a factor of 100 for SiC devices after 10 Mrad γ ray exposition. The experiments indicate also that the measured leakage currents of the order of pA are dominated by surface leakage.
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Ding, Wen He. "Passivation of stainless steels for medical applications." Thesis, University of Macau, 2006. http://umaclib3.umac.mo/record=b1636557.
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Yang, Xiaofan. "Corrosion and passivation of molybdenum-bearing alloys." Thesis, University of Surrey, 1995. http://epubs.surrey.ac.uk/843256/.
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Molybdenum-bearing alloys are widely used in industry because of their excellent corrosion resistance. However, the role of molybdenum in passivation is a subject which has been a matter for discussion and controversy for many years. In the previous work carried out in this laboratory, Professor Castle and Dr Qiu suggested that molybdenum oxide might provide the nuclei for formation of the passive film. This hypothesis is the basis of the present work. In order to find out the evidence for the existence of the molybdenum oxide nuclei, furthermore, to establish a model of passivation for the molybdenum-bearing alloys, the passivation of molybdenum-bearing alloys are investigated by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), especially in-situ AFM, in conjunction with SEM and TEM. During the passivation study, it was found that the chemical composition on anodically polarised surfaces varied with potential. For 516 alloy, the peak value of molybdenum in the surface is at the low potential of the passive region close to the Flade potential. Therefore, molybdenum exerts its greatest function in this potential region. A further AFM study at this potential revealed, surprisingly, that a platelet layer formed on the passivation surface. The dendritic structure on the surface of the platelets presented under the high resolution of STM, which shows the crystallization property of the platelets. These platelets are mainly composed of chromium and molybdenum oxides and they are only found in the passivation of the molybdenum-bearing alloy, so the formation of the platelets may be associated with molybdenum nucleation in passivation. The in-situ AFM studies provide the evidence for the formation and disappearance of the platelets during the passivation of molybdenum-bearing alloys, i.e. the platelets form at the early stage of passivation and they gradually merge into the passive film if they are not disturbed by the environment. Based on the above finding, the role of molybdenum in passivation is proposed as following: molybdenum oxide precipitated on the surface seeds chromium oxide to form platelets at the early stage of passivation and the formed platelet layer prohibits the dissolution of the passive species from the metal. By this way, molybdenum facilitates the formation of the passive film on alloys. Using Fe-Cr-Mo duplex stainless steels, the corrosion of molybdenum-bearing alloys are studied in HCl and the kinetics of the corrosion are traced by in-situ AFM. During corrosion, it was observed that the ferritic phase in duplex stainless steel dissolves more rapidly than the austenitic phase and the dissolution occurs on the austenite preferentially along grain boundaries, sub-grain boundaries and the planes with high energy. By switching the electrochemical condition from active dissolution to passivation and then changing it back, it is found that under the passivation condition after the active dissolution, the corrosion changes from selective dissolution of the crystallographic feature to general corrosion. This situation persists even though the electrochemical condition changes back to the active condition from the passivation condition. Since AFM is a new technique and this is one of the first attempts at applying it to a corrosion study, an in-depth explanation of the images obtained from a corroded rough surface is an important topic on which so far little work has been reported. In this study, therefore, the artifacts and the reality of the structure in AFM images obtained in the corrosion study are discussed.
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Krishnamurthy, Rajesh. "Passivation of GaAs and GaInAsP semiconducting materials." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0005/NQ31174.pdf.
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Jarjoura, George. "Effect of nickel on copper anode passivation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0015/MQ48272.pdf.
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Basque, Daniel F. "Passivation of stainless steels in reactor coolants." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0017/MQ54663.pdf.
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Wolborski, Maciej. "Termination and passivation af silicon carbide devices /." Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-439.
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Chang, Wai-Kit. "Porous silicon surface passivation and optical properties." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/41426.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1996."June 1996."
Includes bibliographical references (leaves 84-85).
by Wai-Kit Chang.
S.M.
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Sun, Shiyu. "Germanium surface cleaning, passivation, and initial oxidation /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Michalak, David Jason Gray Harry B. "Physics and chemistry of silicon surface passivation /." Diss., Pasadena, Calif. : Caltech, 2006. http://resolver.caltech.edu/CaltechETD:etd-05082006-074414.
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Duncan, Steven James. "Passivation and repassivation of aluminium and its alloys." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.237673.
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Benrabah, Sabria. "Passivation des matériaux III-N de type GaN." Thesis, Lyon, 2021. http://www.theses.fr/2021LYSE1310.
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Pour répondre aux demandes de développement de nouveaux produits dans les domaines des convertisseurs électroniques de puissance pour les voitures électriques, des panneaux solaires, des éoliennes et des nouvelles technologies d'éclairage à base de LED ou de composants RF, la recherche s'est concentrée sur les matériaux à large bande interdite directe, dont le nitrure de gallium (GaN). Le GaN a suscité un grand intérêt en raison de ses propriétés exceptionnelles pour les dispositifs électroniques de puissance de la prochaine génération. Avec une vitesse de saturation élevée et une tension de fonctionnement élevée, les dispositifs à base de GaN peuvent fonctionner à haute fréquence et avec un excellent rendement, ce qui fait du GaN un matériau de choix dans les applications de puissance. Cependant, le développement des matériaux III-N est encore immature, notamment en ce qui concerne le contrôle de la qualité des différentes interfaces au sein des dispositifs. La présence d'une forte densité d'états d'interfaces peut être à l'origine de dysfonctionnements du dispositif. Par conséquent, la compréhension et le contrôle de la surface du GaN constituent un défi pour une éventuelle intégration industrielle future. Aujourd'hui, il n'existe pas de préparation de surface standard appropriée et efficace pour le GaN. Afin d'étudier ce problème, ce projet de thèse a été réalisé dans le cadre d'une collaboration entre le CEA-LETI (Grenoble), le LTM (Grenoble) et les laboratoires CP2M (Catalyse, Polymérisation, Procédés et Matériaux, Lyon). Les principaux objectifs de ce projet sont, d'une part, de comprendre la chimie de surface suite à différentes préparations de surface, et d'autre part, de mettre en place la configuration des liaisons de surface. Ce projet de thèse s'est donc concentré sur la préparation et la caractérisation de l'extrême surface de GaN après divers traitements chimiques et physiquesTo meet demands for the development of new products in the fields of power electronic convertors for electric cars, solar panels, wind turbines, and new LED-based lightening technologies or RF components, research has focused on direct wide bandgap materials, including Gallium Nitride (GaN). GaN has attracted significant interest due to its exceptional properties for next-generation power electronic devices. With a high saturation velocity and a high operating voltage, GaN-based devices can operate at high frequency and with excellent efficiency, making GaN a material of choice in power applications. However, the development of III-N materials is still immature, especially in terms of quality control of the various interfaces within the devices. The presence of high density of interfaces states can be the cause of device malfunctions. Therefore, understanding and controlling the surface of GaN is a challenge for possible future industrial integration. Today, there is no suitable and effective standard surface preparation of GaN. In order to investigate this problem, this PhD project was carried out in a collaboration between CEA-LETI (Grenoble), LTM (Grenoble) and CP2M laboratories (Catalysis, Polymerisation, Process and Materials, Lyon). The main objectives of this project are, first, to understand the surface chemistry following various surface preparations, and second, to set up the configuration of surface bonds. Therefore, this PhD project focused on the preparation and characterisation of the extreme surface of GaN after various chemical and physical treatments
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XU, MAN. "PASSIVATION OF BATCH-GALVANIZED STEEL BY SILANE TREATMENT." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1195660288.
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Antu, Antara Debnath. "Morphology and Surface Passivation of Colloidal PbS Nanoribbons." Bowling Green State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1499383746861722.
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Lee, Byung-Wook. "Orientation du procès : transitivité et passivation en coréen." Paris 5, 1994. http://www.theses.fr/1994PA05H051.
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La thèse contient deux parties. La première partie est consacrée à la transitivité. La dichotomie intransitif transitif peut se faire, en considérant la teneur axiologique du nom, selon la compatibilité avec le groupe nominal affuble de la postposition appelle accusative. En se fondant sur la notion de valence, on écarte de la zone actancielle la postposition accusative qui ne sert pas à caractériser le verbe : une description détaillée est donnée à l'expression spatiale. On dégage diverses contributions de la postposition accusative à la réalisation sémantique du procès concurremment avec le sémantisme verbal. Cela permet de situer le procès sur une échelle de la transitivité. La deuxième partie traite des procèdes de passivation. Plusieurs facteurs qui entrainent la dissymétrie entre l'actif et passifs sont présentes : le trait sémantique anime inanimé du sujet, l'aspect et l'instrument vis-à-vis de la cause. En proposant une catégorie de prédicat passif on explicite la construction passive comprenant le groupe nominal marque par la postposition accusative. L'identité for lemme du morphème passif et causatif, supposée par de nombreux linguistes, est réexaminée en tenant compte des faits diachroniques.
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Géniès, Sylvie. "Étude de la passivation de l'électrode carbone-lithium." Grenoble INPG, 1998. http://www.theses.fr/1998INPG0008.
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Le phenomene de la passivation de l'electrode carbone-lithium utilisee comme pole negatif dans la batterie lithium-ion est d'une importance cruciale dans les caracteristiques du fonctionnement de cette electrode. Il en fixe la capacite reversible (ou utile), la duree de vie et le taux d'autodecharge. Ce travail est une contribution a la comprehension des processus chimiques et electrochimiques survenant a la surface de l'electrode au cours de l'echange du lithium avec une solution electrolytique a base d'un ou plusieurs solvant(s) organique(s) et d'un sel de lithium et conduisant a la formation d'un film de passivation. Apres une presentation bibliographique qui situe l'etude dans son contexte national et international, le travail experimental s'adresse dans un premier temps au role des parametres qui influent sur le processus de passivation tels que la nature de l'anion du sel de lithium et celle du materiau carbone ainsi que la composition de l'electrolyte. La caracterisation de ce film obtenu par des methodes chimiques ou electrochimiques utilise une large gamme de techniques : drx, meb, met, microscopie a champ proche (afm), ir-tf, rmn, esca, atg et dsc. Les techniques electrochimiques sont aussi variees : chronoamperometrie, chronopotentiometrie, impedance complexe et voltamperometrie cyclique. Les resultats obtenus sont pour la plupart originaux. Ainsi, les analyses de la composition chimique du film par esca et par ir-tf sont non seulement completes et nouvelles mais mettent en evidence pour la premiere fois le caractere polymere du film. Ce resultat devrait avoir des repercutions importantes sur l'elaboration ex situ du film pour une etude plus approfondie. L'observation du film forme sur un graphite hautement oriente par afm a permis d'obtenir les images les plus precises et les plus claires jamais publiees. L'etude electrochimique est completee par une synthese chimique du film par une methode originale. L'utilisation de ce film comme electrolyte de type plastifie a ete demontree.
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Libraro, Sofia. "Advanced characterization of fired passivating contacts for silicon solar cells." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19294/.
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I contatti passivanti basati sul silicio policristallino permettono di ottenere elevate efficienze e allo stesso tempo sono compatibili con i processi industriali ad alte temperature. Tra essi, l'approccio detto fired passivating contacts (FPC) permette una semplice integrazione con gli attuali processi industriali, poiché la formazione della giunzione è basata sul processo di firing, utilizzato dall'industria per la metallizzazione delle celle.
Il lavoro presentato in questa tesi è stato sviluppato in collaborazione tra il Dipartimento di Fisica e Astronomia dell'Università di Bologna e il PV-Lab della École polytechnique fédérale de Lausanne (EPFL), Svizzera. Lo scopo del lavoro è approfondire i principi di funzionamento dei fired passivating contacts e comprendere i meccanismi che controllano il trasporto elettronico in questi dispositivi.
Gli esperimenti sono stati condotti sia su campioni di prova sia su celle solari contenenti i contatti passivanti. Le tecniche utilizzate hanno permesso lo studio della qualità di passivazione dei layers (fotoluminescenza e quasi-steady-state photoconductance) e delle loro proprietà di trasporto elettronico, tramite transmission line measurements e misure di corrente-tensione su celle. Inoltre, le proprietà ottiche dei campioni sono state studiate mediante spettroscopia di fototensione superficiale, spettroscopia infrarossa a trasformata di Fourier, ellissometria e spettroscopia Raman.
I risultati principali includono l'identificazione delle ottimali condizione di fabbricazione (temperatura e durata del firing) per questo tipo di campioni e lo studio dell'evoluzione delle loro proprietà con differenti condizioni di preparazione. Sono stati osservati due differenti meccanismi di trasporto elettronico nei FPCs, e sono state individuate le condizioni in cui uno prevale sull'altro.
Inoltre, è stato studiato il trasporto nelle celle solari e come le proprietà dei passivating contacts influenzino il funzionamento delle celle.
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Song, Yang Photovoltaics & Renewable Energy Engineering Faculty of Engineering UNSW. "Dielectric thin film applications for silicon solar cells." Publisher:University of New South Wales. Photovoltaics & Renewable Energy Engineering, 2009. http://handle.unsw.edu.au/1959.4/44486.
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Dielectric thin films have a long history in silicon photovoltaics. Due to the specific physical properties, they can function as passivation layer in solar cells. Also, they can be used as antireflection coating layers on top of the devices. They can improve the back surface reflectance if proper dielectric layers combination is used. What??s more, they can protect areas by masking during chemical etching, diffusion, metallization among the whole fabrication process. Crystalline silicon solar cell can be passivated by two ways: one is to deposit dielectric thin films to saturate the dangling bonds; the other is to introduce surface electrical field and repel back the minority carriers. This thesis explores thermally grown SiO2 and sputtered Si3N4(:H) to passivate n-type and thermal evaporation AlF3 to passivate p-type Float Zone silicon wafers, respectively. Sputtering is a cheap passivation method to replace PECVD in industry usage, but all sputtered samples are more likely to have encountered surface damage from neutral Ar and secondary electrons, both coming from the sputtered target. AlF3/SiO2 multi-layer stack is a negative charge combination; p inversion layer will form on the wafer surface. Light trapping is an important part in solar cell research work. In order to enhance the reflectance and improve the absorption possibility of near infrared photons, especially for high efficiency PERL cell application, the back surface structure is optimized in this work. Results show SiO2/Ag is a very good choice to replace SiO2/Al back reflectors. The maximum back surface reflectance is 97.82%. At the same time, SiO2/Ag has excellent internal angle dependence of reflectance, which is beneficial for surface textured cells. A ZnS/MgF2/SiO2/Al(Ag) superlattice can improve the back reflectance, but it is sensitive to incident angle inside the silicon wafer. If planar wafers are used to investigate all kinds of back reflectors, and an 8 degrees incident angle is fixed for typical spectrometry measurement, the results are easy to predict by Wvase software simulation. If a textured surface is considered, the light path inside the silicon wafer is very complicated and hard to calculate and simulate. The best way to evaluate the result is through experiment.
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Mzali, Sana. "Méthodologie de fabrication de transistors à base de Graphène : application aux composants optoélectroniques hyperfréquences." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLX086/document.
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Depuis sa découverte en 2004, le graphène n’a cessé de capter l’intérêt de la communauté scientifique grâce à ses innombrables propriétés et à la diversité de ses applications potentielles. Néanmoins, son implémentation à l’échelle industrielle exige encore beaucoup de contraintes et notamment concernant la stabilité de ses performances.L’objectif de cette thèse est de développer un procédé de fabrication de dispositifs intégrant une couche de graphène faiblement dopée et présentant des caractéristiques électriques stables. Le graphène, étant un matériau extrêmement sensible à l’environnement, il s’est avéré primordial de le protéger afin d’avoir un bon contrôle sur ses propriétés. Pour ce faire, plusieurs approches technologiques ont été abordées et analysées à l’aide d’une étude statistique des caractéristiques de plus de 500 transistors. Le procédé optimal intègre une couche de « protection » du graphène réalisée après son transfert et la passivation des dispositifs fabriqués avec une couche d’oxyde. Grâce à cette méthode, 75% des transistors fabriqués sont fonctionnels, présentent une faible hystérèse et sont stables dans le temps, ce qui constitue des critères indispensables pour l’intégration du graphène dans des composants discrets en particulier pour l’optoélectronique.Par la suite, le procédé technologique développé a été adapté à la fabrication de lignes coplanaires à base de graphène pour la photodétection hyperfréquence. Des valeurs de photo-courant, proches de celles de la littérature (0.15 mA/W), ont été mesurées avec un laser 1.55 µm modulé à des fréquences allant jusqu’à 40 GHz. Cette technologie est maintenant évaluée pour la fabrication de mixeurs optoélectroniques haute fréquenceSince its discovery in 2004, graphene has attracted the attention of the scientific community due to its unique properties as well as the diversity of its potential applications. Nevertheless, its implementation at industrial scale still requires many challenges including its performance stability.The objective of my PhD is to develop a technological process for the fabrication of devices integrating low-doped graphene and exhibiting stable electrical characteristics. As graphene is extremely sensitive to the environment, it is crucial to protect its surface to accurately control its properties. To do this, several technological approaches have been analyzed using the statistical characteristics of more than 500 transistors. The optimal process integrates a “protection” layer after graphene transfer and the passivation of the fabricated devices with an oxide layer. 75% of the passivated transistors were functional, with low hysteresis and time-stable performances. These criteria are essential for the integration of graphene in discrete components, in particular for optoelectronic devices.Subsequently, the technological process developed was adapted for the fabrication of graphene based coplanar waveguides for high frequency photodetection. We report on a measured photocurrent of 0.15 mA/W with a 1.55 µm laser modulated up to 40 GHz. This technology is currently studied for the fabrication of high frequency optoelectronic mixers
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Flynn, Christopher Richard ARC Centre of Excellence in Advanced Silicon Photovoltaics & Photonics Faculty of Engineering UNSW. "Sputtering for silicon photovoltaics: from nanocrystals to surface passivation." Awarded by:University of New South Wales. ARC Centre of Excellence in Advanced Silicon Photovoltaics & Photonics, 2009. http://handle.unsw.edu.au/1959.4/44686.
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Deposition of thin material films by sputtering is an increasingly common process in the field of silicon (Si)-based photovoltaics. One of the recently developed sputter-deposited materials applicable to Si photovoltaics comprises Si nanocrystals (NCs) embedded in a Si-based dielectric. The particular case of Si nanocrystals in a Silicon Dioxide (SiO2) matrix was studied by fabricating metal-insulator-semiconductor (MIS) devices, in which the insulating layer consists of a single layer of Si NCs in SiO2 deposited by sputtering (Si:NC-MIS devices). These test structures were subjected to impedance measurements. The presence of Si NCs was found to result in two distinct capacitance peaks. The first of these peaks is attributable to the small signal response of states at the insulator/substrate interface, enhanced by the presence of fixed charge associated with the NC layer. The second peak, which occurs without precedent, is due to external inversion layer coupling, in conjunction with a transition between tunnel-limited and semiconductor-limited electron current. Si:NC-MIS devices are also potential test structures for energy-selective contacts, based on SiO2/Si NC/SiO2 double barrier structures fabricated by sputtering. Using a one-dimensional model, current-voltage (I-V) curve simulations were performed for similar structures, in which the Si NCs are replaced by a Si quantum well (QW). The simulations showed that for non-degenerately doped Si substrates, the density of defects in the SiO2 layers can strongly influence the position of I-V curve structure induced by QW quasi-bound states. Passivation of crystalline Si (c-Si) surfaces by sputter-deposited dielectric films is another major application of sputtering for Si photovoltaics. This application was explored for the cases of sputtered SiO2 and hydrogenated Silicon Oxy-Carbide (SiOC:H). For the case of sputtered SiO2, an effective surface recombination velocity of 146 cm/s was achieved for an injection level of 1E15 cm???3. The investigated SiOC:H films were found to be unsuitable for surface passivation of Si, however their passivation performance could be slightly improved by first coating the Si surface with a chemically-grown or sputtered SiO2 layer. The investigations performed into specific aspects of sputter-deposited SiO2, Si NCs, and SiOC:H have highlighted important properties of these films, and confirmed the effectiveness of sputtering as a deposition technology for Si photovoltaics.
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Lu, Mingzhe. "Nickel oxide passivation processing for microstrip gas chamber detector." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq24187.pdf.
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Liu, Chuan. "The passivity and passivation of the guillotined aluminium electrode." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338074.
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Wilcox, G. D. "Molybdate-based passivation treatments for tin, tinplate and zinc." Thesis, Loughborough University, 1986. https://dspace.lboro.ac.uk/2134/7482.
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The level of toxicity of chromate conversion coating solutions has led to a search for alternatives. Molybdate has been considered, being a relatively non-toxic analogue from group (VIA) of the periodic table. The ability of molybdate to perform as an inhibitor in aerated conditions is well-reported, although its application in conversion coatings is less widely documented. The experimental work reported in this thesis was to a large extent based on potentiodynamic polarisation which is considered a powerful tool for evaluating potential coating solutions. The cathodic polarisation characteristics of zinc in group (VIA) oxy-anion solutions has been studied quantitatively. The effect of temperature, pH and aeration has been examined. The film-forming ability of molybdate-based solutions such as molybdate-orthophosphoric acid (MP), molybdate-orthophosphoric acid-nitrate and molybdate-orthophosphate has been examined with respect to a tin, tinplate or zinc substrate. Films were formed electrochemically (anodically and cathodically) or by a simple immersion technique. The performance of such coatings has been studied using classical corrosion tests such as sulphide stain and salt spray. The cathodic reduction characteristics of molybdate solutions have also been examined in detail with respect to possible lower valency films being produced (possibly as a result of molybdate's complex electrochemistry) on tinplate, zinc and platinum metal surfaces. Experimental results have indicated that simple, relatively dilute, molybdate solutions at pH 3 are capable of imparting good staining resistance to tinplate in sulphide stain tests. However, other mixed systems have proved less successful, only molybdate-orthophosphoric acid providing acceptable protection on tin foil. Simple immersion techniques in dilute, pH 5 molybdate solutions have provided moderate protection on zinc in 24-hour salt spray tests. Inflections exhibited on cathodic polarisation curves of tinplate in simple molybdate solutions have been attributed to a physical degradation of the coating as opposed to a reduction step.
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Lu, Haichang. "Electronic structure, defect formation and passivation of 2D materials." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/284926.
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The emerging 2D materials are potential solutions to the scaling of electronic devices to smaller sizes with lower energy cost and faster computing speed. Unlike traditional semiconductors e.g. Si, Ge, 2D materials do not have surface dangling bonds and the short-channel effect. A wide variety of band structure is available for different functions. The aim of the thesis is to calculate the electronic structures of several important 2D materials and study their application in particular devices, using density functional theory (DFT) which provides robust results. The Schottky barrier height (SBH) is calculated for hexagonal nitrides. The SBH has a linear relationship with metal work function but the slope does not always equal because Fermi level pinning (FLP) arises. The chemical trend of FLP is investigated. Then we show that the pinning factor of Si can be tuned by inserting an oxide interlayer, which is important in the application to dopant-free Si solar cells. Apart from contact resistance, we want to improve the conductivity of the electrode. This can be done by using a physisorbed contact layer like FeCl3, AuCl3, and SbF5 etc. to dope the graphene without making the graphene pucker so these dopants do not degrade the graphene's carrier mobility. Then we consider the defect formation of 2D HfS2 and SnS2 which are candidates in the n-type part of a tunnel FET. We found that these two materials have high mobility but there are also intrinsic defects including the S vacancy, S interstitial, and Hf/Sn interstitial. Finally, we study how to make defect states chemically inactive, namely passivation. The S vacancy is the most important defect in mechanically exfoliated 2D MoS2. We found that in the most successful superacid bis(trifluoromethane) sulfonamide (TFSI) treatment, H is the passivation agent. A symmetric adsorption geometry of 3H in the -1 charge state can remove all gap states and return the Fermi level to the midgap.
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Cartier, Alice. "Problemes de linguistique contrastive indonesien chinois. Transitivite et passivation." Paris 7, 1986. http://www.theses.fr/1986PA070064.
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Cette etude contrastive vise non seulement la recherche des differences mais surtout celle des points communs a deux langues non-apparentees afin d'en degager, dans la mesure du possible, des points generalisables. S'agissant d'une approche semanticogrammaticale nous nous sommes proposees de mettre en evidence certaines caracteristiques du langage a travers la morphologie et la syntaxe des deux langues. Puisque le passif est envisage comme une consequence de la transitivite, nous definissons tout d' abord la transitivite. De la notion de transitivite de p. Hopper et s. Thompson (language (1980 : 251-299) ) nous avons extrait les parametres pertinents pour notre travail. La transitivite ne se mesurant pas au nombre des parametres positifs ou negatifs , nous avons introduit la notion de structures de transitivite, dans lesquelles tel ou tel parametre positif negatif est obligatoirement associe a tel ou tel parametre positif negatif. Les facteurs semantiques determinant les structures de transitivite sont les relations entre les actants et l'aspect. Nous sommes donc amene d'une part a introduire la grammaire des cas et d'autre part a distinguer des enonces transitifs accomplis des enonces non-accomplis. La definition des roles semantiques du sujet et de l'objet en termes de grammaire des cas, en plus de l'analyse de l'aspect permet de classer les constructions transitives et de definir leurs proprietes. 1) les enonces accomplis sont orientes vers le resultat de l'evenement, tandis que les enonces nonaccomplis sont orientes vers l'evenement. 2) les deux types d'enonces transitifs sont, dans les deux langues, distingues sur le plan morphologique. . .This is a contrastive study of two independant languages focusing on their differences but mostly on their common properties. The aim is to discover the underlying properties of transitivity and passivization through an investigation of the morphology and the syntax of these two languages. Passive is viewed as the implication of transitivity. Transitivity is taken in the sense of hopper & thompson (language 1980 : 251-99), i. E. As involving a number of parameters concerned with the effectiveness of the event. According to both authors transitivity operates not only at the sentence level but also at the discourse level. In as much as we are solely dealing with the sentence level, only parameters relevant to this level are taken into consideration. Secondly, both authors did not investigate how the parameters are applied to different languages. Thus the introduction of the concept of transitive structures, in which the presence absence of a parameter x triggers the presence absence of a parameter y is intended as a
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Torchio, Philippe. "Passivation volumiques et superficielles de photopiles au silicium multicristallin." Aix-Marseille 3, 1992. http://www.theses.fr/1992AIX30022.
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Des traitements susceptibles d'ameliorer le materiau et le composant ont ete appliques a des plaquettes de silicium multicristallin et a des photopiles. L'effet getter externe par diffusion superficielle de phosphore a ete utilise pour augmenter les longueurs de diffusion et ameliorer les caracteristiques courant-tension de diodes mesa. Un montage a commande et exploitation automatisee de ces caracteristiques a ete mis au point, facilitant l'interpretation des valeurs relativement elevees des courants d'obscurite dans les structures etudiees. L'oxydation thermique par un flux d'oxygene sec a ete employee pour reduire la vitesse de recombinaison superficielle s, et une technique d'evaluation de s a ete mise au point, a partir de l'exploitation de la reponse spectrale dans l'ultra-violet. Ces oxydations ont ete testees avec des petites photopiles realisees au laboratoire, ce qui a permis de suivre l'evolution de s, et celle de l'epaisseur d'oxyde x. La vitesse de croissance de l'oxyde de la region superficielle de l'emetteur, fortement dopee au phosphore, se revele beaucoup plus elevee que celle admise pour une region peu dopee; cette difference est due a la forte densite de phosphore qui introduit des sites supplementaires de reaction par l'intermediaire de lacunes de silicium. De plus, x varie lineairement avec la duree de l'oxydation entre 800c et 900c, jusqu'a 800 a au moins, ce qui s'expliquerait par une forte augmentation du coefficient de diffusion de l'oxygene dans la silice, attribuable a des inclusions de verre de phosphore et a une reduction de l'enthalpie reactionnelle de l'oxydation. Grace a des oxydations successives, s a ete ramenee a environ 2. 10#4 cm. S##1. Cette valeur encore elevee, peut etre due a la presence de phosphore piege a l'interface, ou a la prise en compte involontaire des recombinaisons auger dans l'emetteur, meme apres son amincissement
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LE, GAL LA SALLE-MOLIN ANNIE. "Corrosion, passivation et protection du cuivre en solutions aqueuses." Paris 6, 1991. http://www.theses.fr/1991PA066198.
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La premiere partie de ce travail etudie les differents phenomenes accompagnant la corrosion du cuivre en solution aqueuse. Les principales conclusions des travaux precedemment publies dans ce domaine sont tout d'abord rassemblees et interpretees a la lumiere d'une etude thermodynamique des equilibres existant entre les differentes especes du cuivre. Les essais experimentaux effectues ensuite ont montre que la corrosion s'accompagnait de la formation d'une couche complexe dans laquelle coexistent oxides cuivreux et cuivriques, puis de sa desagregation partielle. Plusieurs methodes complementaires ont ete employees: methodes physiques d'analyse de surface, absorptiometrie et polarographie, ainsi que trace de courbes intensite potentiel et mesures d'impedance. Ces dernieres, et notamment l'etude des fonctions de transfert masse/potentiel et flux de matiere/potentiel (methode disque-anneau) nous ont egalement permis une premiere approche dans l'elaboration d'un mecanisme de corrosion du cuivre. La deuxieme partie de ce travail etudie differents moyens de lutte contre la corrosion du cuivre. L'utilisation d'un inhibiteur de corrosion, le benzotriazole, dont l'origine des proprietes inhibitrices a ete expliquee, s'avere possible. Enfin, la formation de revetements protecteurs prealablement a l'utilisation du metal au contact du milieu corrosif, a ete envisagee dans le cas ou l'emploi d'inhibiteurs n'est pas realisable. Nous avons ainsi mis au point la realisation de depots de benzotriazolate du cuivre ou de diphosphate de cuivre et teste les qualites protectrices de ceux-ci
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Bouvier, Odile de. "Corrosion et passivation des fontes amorphes en milieu cimentaire." Grenoble INPG, 1990. http://www.theses.fr/1990INPG0004.
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Les fibres de fonte, alliages amorphes industriels utilises comme fibres de renforcement des betons, sont naturellement recouverts d'une couche protectrice epaisse (10 nm a 50 nm); cette couche superficielle analysee par esca, sims, sdl, est constituee d'oxydes de fer et de chrome(iii) et, en moindre quantite, de silicium. En solution decimale de soude, cette couche est remplacee par un film de passivation (5 nm) constitue d'oxydes de fer et de chrome(iii) et contenant du phosphore lie au sodium. La cinetique globale de formation du film passif, etudiee par voltamperometrie a balayage lineaire en potentiel, est limitee par la diffusion des ions hydroxyde a l'interieur du film. Les proprietes de conduction de ce film, analysees par spectrophotoelectrochimie, sont celles d'un semi-conducteur de type n faisant intervenir de nombreux etats localises dans le gap de mobilite. L'inhibition totale de l'oxydation des ions ferrocyanure et celle, partielle, de la reduction des ions ferricyanure sur l'alliage amorphe sont expliquees par ces proprietes. La resistance electrique de la couche, deduite de la courbe de variation de la charge avec le potentiel, est fonction du potentiel applique; elle varie de 10 ?cm#2 a 200 ?cm#2. Lorsque l'alliage ne presente pas de domaine cristallise et a une teneur nominale en chrome d'au moins 4,3 at. %, il ne subit pas de corrosion en milieu basique aqueux ou cimentaire pendant au moins trois a temperature ambiante
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Pereau, Alban Jean-Joel. "Rear surface passivation for high efficiency silicon solar cells." Thesis, Heriot-Watt University, 2013. http://hdl.handle.net/10399/2828.
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In order to adapt laser grooved buried contact (LGBC) solar cells to a thinner silicon substrate than usually used, we have investigated the reduction of charge carrier loss at the rear surface of p-type silicon wafers by plasma-enhanced chemical vapour deposition (PECVD) of a-Si:H and SiNx films. The efficiency of these passivating films has been measured via the surface recombination velocity (SRV) which is wanted as low as possible. The SRV values of our samples have been compared with the expected theoretical values given by the Shockley-Read Hall (SRH) recombination model. SRH theory is a description of the electron-hole recombination via defects inducing energy levels in the forbidden bandgap. This way of recombination is the predominant mode for semiconductors with indirect bandgaps like silicon. Two influential factors in regard to SRV can be understood from this theory. These two factors are the electron to hole capture cross section ratio and the fixed charge density Qf at the silicon substrate/film interface. These two factors induce an asymmetry between the electron and the hole recombination and are responsible for the excess charge carrier concentration dependence of the SRV. In other words, the SRV depends on the illumination intensity. In this work, the SRV has been measured for an excess charge carrier injection level in the 1.1013-1.1016 cm-3 range and then it has been compared with the theoretical value given by the SRH theory in order to determine the fixed charge density and have an estimation of the defect characteristics including its density. Simulations of LGBC cells under one sun illumination have then been performed using the PC1D5 software. The measured SRV value corresponding to one sun has been integrated in the simulation and the expected efficiency has been extracted as a function of the wafer thickness. It results from this study that 150μm LGBC solar cells can theoretically have an efficiency of 19% by the integration of passivating SiNx films. A second aspect of this work is an effort to understand the relation between the passivating film quality, structure, and the PECVD parameters during deposition. The films have been characterized principally by ellipsometry and also by XPS. All of our SiNx films are located in the Si-rich region (x<1.1) and the passivating quality increases with x.
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Traub, Matthew C. Gray Harry B. "Chemical functionalization and electronic passivation of gallium arsenide surfaces /." Diss., Pasadena, Calif. : California Institute of Technology, 2008. http://resolver.caltech.edu/CaltechETD:etd-07172007-124916.
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Cartier, Alice. "Problèmes de linguistique contrastive indonésien-chinois transitivité et passivation." Lille 3 : ANRT, 1989. http://catalogue.bnf.fr/ark:/12148/cb37596571d.
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Moats, Michael Scott 1970. "Electrochemical characterization of anode passivation mechanisms in copper electrorefining." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282777.
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Anode passivation can decrease productivity and quality while increasing costs in modern copper electrorefineries. This investigation utilized electrochemical techniques to characterize the passivation behavior of anode samples from ten different operating companies. It is believed that this collection of anodes is the most diverse set ever to be assembled to study the effect of anode composition on passivation. Chronopotentiometry was the main electrochemical technique, employing a current density of 3820 A m⁻². From statistical analysis of the passivation characteristics, increasing selenium, tellurium, silver, lead and nickel were shown to accelerate passivation. Arsenic was the only anode impurity that inhibited passivation. Oxygen was shown to accelerate passivation when increased from 500 to 1500 ppm, but further increases did not adversely affect passivation. Nine electrolyte variables were also examined. Increasing the copper, sulfuric acid or sulfate concentration of the electrolyte accelerated passivation. Arsenic in the electrolyte had no effect on passivation. Chloride and optimal concentrations of thiourea and glue delayed passivation. Linear sweep voltammetry, cyclic voltammetry, and impedance spectroscopy provided complementary information. Analysis of the electrochemical results led to the development of a unified passivation mechanism. Anode passivation results from the formation of inhibiting films. Careful examination of the potential details, especially those found in the oscillations just prior to passivation, demonstrated the importance of slimes, copper sulfate and copper oxide. Slimes confine dissolution to their pores and inhibit diffusion. This can lead to copper sulfate precipitation, which blocks more of the surface area. Copper oxide forms because of the resulting increase in potential at the interface between the copper sulfate and anode. Ultimate passivation occurs when the anode potential is high enough to stabilize the oxide film in the bulk electrolyte. The effect of anode impurities or electrolyte concentrations can be related to the formation of one of these films. Reactions occurring after passivation have also been examined. Post-passivation reactions are believed to include silver dissolution, transformation of lead sulfate to lead oxide, and oxygen evolution. Following the sharp potential increase caused by the passivation, silver that has accumulated on the anode surface will dissolve into the electrolyte at a potential between 1.0 and 1.3 V. After the silver has dissolved, the potential increases again at which point the oxidation of lead sulfate to lead oxide occurs. The formation of lead oxide provides a surface with a lower oxygen evolution overpotential. The presence of kupferglimmer also results in a stable lower oxygen evolution potential occurring at approximately 2.0 V.
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Yelundur, Vijay Nag. "Understanding and Implementation of Hydrogen Passivation of Defects in String Ribbon Silicon for High-Efficiency, Manufacturable, Silicon Solar Cells." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/5271.
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Photovoltaics offers a unique solution to energy and environmental problems simultaneously. However, widespread application of photovoltaics will not be realized until costs are reduced by about a factor of four without sacrificing performance. Silicon crystallization and wafering account for about 55% of the photovoltaic module manufacturing cost, but can be reduced significantly if a ribbon silicon material, such as String Ribbon Si, is used as an alternative to cast Si. However, the growth of String Ribbon leads to a high density of electrically active bulk defects that limit the minority carrier lifetime and solar cell performance. The research tasks of this thesis focus on the understanding, development, and implementation of defect passivation techniques to increase the bulk carrier lifetime in String Ribbon Si in order to enhance solar cell efficiency. Hydrogen passivation of defects in Si can be performed during solar cell processing by utilizing the hydrogen available during plasma-enhanced chemical vapor deposition (PECVD) of SiNx:H films. It is shown in this thesis that hydrogen passivation of defects during the simultaneous anneal of a screen-printed Al layer on the back and a PECVD SiNx:H film increases the bulk lifetime in String Ribbon by more than 30 ?A three step physical model is proposed to explain the hydrogen defect passivation. Appropriate implementation of the Al-enhanced defect passivation treatment leads to String Ribbon solar cell efficiencies as high as 14.7%. Further enhancement of bulk lifetime up to 92 ?s achieved through in-situ NH3 plasma pretreatment and low-frequency (LF) plasma excitation during SiNx:H deposition followed by a rapid thermal anneal (RTA). Development of an optimized two-step RTA firing cycle for hydrogen passivation, the formation of an Al-doped back surface field, and screen-printed contact firing results in solar cell efficiencies as high as 15.6%. In the final task of this thesis, a rapid thermal treatment performed in a conveyer belt furnace is developed to achieve a peak efficiency of 15.9% with a bulk lifetime of 140 ?Simulations of further solar cell efficiency enhancement up to 17-18% are presented to provide guidance for future research.
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Wolborski, Maciej. "Characterization of dielectric layers for passivation of 4H-SiC devices." Doctoral thesis, Stockholm : Laboratory of Solid State Electronics, Department of Microelectronics and Applied Physics, Royal Institute of Technology (KTH), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4229.
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Glover, Richard D. "Permanganate passivation of pyrite containing ores scale up and characterization /." abstract and full text PDF (free order & download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1446427.
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Motahari, Sara. "Surface Passivation of CIGS Solar Cells by Atomic Layer Deposition." Thesis, KTH, Kraft- och värmeteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-127430.
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Thin film solar cells, such as Cu(In,Ga)Se2, have a large potential for cost reductions, due to their reduced material consumption. However, the lack in commercial success of thin film solar cells can be explained by lower efficiency compared to wafer-based solar cells. In this work, we have investigated the aluminum oxide as a passivation layer to reduce recombination losses in Cu(In,Ga)Se2 solar cells to increase their efficiency. Aluminum oxides have been deposited using spatial atomic layer deposition. Blistering caused by post-deposition annealing of thick enough alumina layer was suggested to make randomly arranged point contacts to provide an electrical conduction path through the device. Techniques such as current-voltage measurement, photoluminescence and external quantum efficiency were performed to measure the effectiveness of aluminum oxide as a passivation layer. Very high photoluminescence intensity was obtained for alumina layer between Cu(In,Ga)Se2/CdS hetero-junction after a heat treatment, which shows a reduction of defects at the absorber/buffer layers of the device.
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Jafari, A. H. "The effect of hydrogen on the passivation process of iron." Thesis, London Metropolitan University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278931.
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Gemmill, R. J. "The passivation of aluminium in inhibited red fuming nitric acid." Thesis, University of Nottingham, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376493.
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Zhang, Qiuhong. "Carbon based passivation layers for ultra-high voltage Si devices." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609703.
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"Passivation and Dissolution of Alloys." Doctoral diss., 2020. http://hdl.handle.net/2286/R.I.62962.
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abstract: The passivity of metals is a phenomenon of vast importance as it prevents many materials in important applications from rapid deterioration by corrosion. Alloying with a sufficient quantity of passivating elements (Cr, Al, Si), typically in the range of 10% - 20%, is commonly employed to improve the corrosion resistance of elemental metals. However, the compositional criteria for enhanced corrosion resistance have been a long-standing unanswered question for alloys design. With the emerging interest in multi-principal element alloy design, a percolation model is developed herein for the initial stage of passive film formation, termed primary passivation. The successful validation of the assumptions and predictions of the model in three corrosion-resistant binary alloys, Fe-Cr, Ni-Cr, and Cu-Rh supports that the model which can be used to provide a quantitative design strategy for designing corrosion-resistant alloys. To date, this is the only model that can provide such criteria for alloy design.The model relates alloy passivation to site percolation of the passivating elements in the alloy matrix. In the initial passivation stage, Fe (Ni in Ni-Cr or Cu in Cu-Rh) is selectively dissolved, destroying the passive network built up by Cr (or Rh) oxides and undercutting isolated incipient Cr (Rh) oxide nuclei. The only way to prevent undercutting and form a stable protective passive film is if the concentration of Cr (Rh) is high enough to realize site percolation within the thickness of the passive film or the dissolution depth. This 2D-3D percolation cross-over transition explains the compositional dependent passivation of these alloys. The theoretical description of the transition and its assumptions is examined via experiments and kinetic Monte Carlo simulations. The initial passivation scenario of the dissolution selectivity is validated by the inductively coupled plasma mass spectrum (ICP-MS). The electronic effect not considered in the kinetic Monte Carlo simulations is addressed by density functional theory (DFT). Additionally, the impact of the atomic configuration parameter on alloy passivation is experimentally measured, which turns out to agree well with the model predictions developed using Monte Carlo renormalization group (MC-RNG) methods.Dissertation/Thesis
Doctoral Dissertation Materials Science and Engineering 2020
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Wang, Hsing-Kai, and 王星凱. "Photolithography glass passivation process improvement." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/90041955442149126931.
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碩士國立臺灣海洋大學
電機工程學系
100
Abstract In this thesis glass passivation process(GPP) use to improve the device leakage current capacity. By photolithography and glass firing process to achieve it’s purpose. The subject matter of this research, TVS(Transient Voltage Suppressor) greater than 100 volts of plant components, the main wafer 4inch、die size is 80mil, the purpose of this research focus on lithography process, use design of experiment (DOE) system to define the best parameters of process and effectively enhance the process stability and yield of device. The main results of this study, the glass passivation process improvement to optimize the parameter settings in the experimental design, mass production trial production results, the glass under cut to improve by more than 50%.