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1
Roux, Sophie. "Conversion de fréquence vers les grandes longueurs d'onde dans des guides d'onde en semi-conducteurs à orientation périodique." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT296/document.
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Le développement de sources moyen infrarouge compactes et accordables dans les gammes de transmission de l’atmosphère présente un intérêt majeur dans les secteurs de la défense et de la sécurité. Les sources paramétriques à quasi-accord de phase en configuration guidée sont prometteuses pour gagner en compacité puisque l’on réduit la puissance de pompe nécessaire par rapport aux sources « massives ». Le premier axe de la thèse consiste à étudier des guides d’onde en arséniure de gallium périodiquement orientés (OP-GaAs) adaptés à un pompage par laser fibré et à des puissances relativement élevées. Le second vise à étudier de façon novatrice la possibilité d’intégrer dans un composant monolithique une diode laser en matériaux antimoniures avec un convertisseur de fréquence en antimoniure de gallium (GaSb). L’enjeu dans les deux cas est de réduire au maximum les pertes à la propagation dans ces guides d’onde pour exploiter pleinement leurs propriétés non-linéaires.Ce travail de thèse a permis de modéliser des structures de guides d’onde ambitieuses pour réduire les pertes, de développer les briques technologiques nécessaires à la fabrication de guides d’onde OP-semi-conducteur faibles pertes et de faire de premières caractérisations de ces composants dans le moyen-infrarouge. Les performances de guides d’onde GaAs ruban enterrés ou non ont pu être comparées, donnant une réduction des pertes d’un facteur trois avec des rubans enterrés. Plusieurs générations de guides d’onde GaSb ont vu le jour, et montrent des performances à l’état de l’art des structures en GaAs. En conséquence, diverses solutions ont été explorées pour intégrer une diode laser en matériaux antimoniures avec le guide d’onde convertisseur de fréquenceThe development of compact and tunable mid-infrared laser sources in the atmospheric transmission windows presents a major interest for several security and defense applications. Quasi-phase-matched parametric sources in guided wave configuration are promising solutions to enhance compactness, because of the reduction in pump power requirements with respect to bulk devices.The first axis of this thesis consists in studying orientation-patterned gallium arsenide (OP-GaAs) waveguides, adapted to fiber laser pumping and to relatively high pump power. The second axis is devoted to the original idea of integrating an antimonide based laser diode with a gallium antimonide (GaSb) frequency converter in a monolithic component. The goal in both cases is to minimize propagation losses in those waveguides to exploit the whole potential of their non-linear properties.This work led to model ambitious low-loss waveguides structures, to develop the technological fabrication steps necessary for OP-semiconductor waveguides manufacturing, and to characterize these components in the mid-infrared. The first buried ridge GaAs waveguide structure has been compared to the ridge one, giving a reduction of a factor three in the propagation losses. Several generations of GaSb waveguides have come forward, with constant losses improvement and reach GaAs state-of-the-art performances. Lastly, multiple solutions have been explored in order to integrate an antimonide-based laser diode with the frequency converter waveguide
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Galibert, Jean. "Transport quantique dans des semiconducteurs de type iii-v : effet shubnikov-de haas dans l'antimoniure de gallium, effet magnetophonon dans l'antimoniure d'indium." Toulouse 3, 1987. http://www.theses.fr/1987TOU30286.
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Determination des potentiels de deformation de la bande de conduction de gasb. Effets de contraintes selon 111 , en bon accord avec des resultats anterieurs, et selon 100, en desaccord avec la theorie. Determination du facteur de lande de gasb a partir des oscillations shubnikov-de haas dans la bande l, resolues en spin. Interpretation. Etude des surstructures qui apparaissent sur les spectres de resonance magnetophonon de insb. La definition des pics a permis de lever des ambiguites
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Garandet, Jean-Paul. "Etude des phénomènes de transport et des défauts cristallins dans des alliages Ga-Sb et Ga-In-Sb élaborés par la méthode Bridgman." Grenoble INPG, 1989. http://www.theses.fr/1989INPG0058.
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Sanchez, Dorian. "Étude et conception d’un nouveau système de confinement pour le VCSEL GaSb émettant dans le moyen-infrarouge." Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20204/document.
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Ce travail de thèse porte sur l'étude et la réalisation de Lasers à Emission par la Surface à Cavité Verticale pompés électriquement (EP-VCSELs) à base d'antimoniures émettant dans le moyen-infrarouge au-delà de 2 µm. Ces VCSELs proposent des caractéristiques intéressantes pour la détection de gaz tel qu'une émission monomode et une large accordabilité sans saut de mode. L'objectif de ce travail était de développer de tels composants. La première partie de ce mémoire présente les propriétés des couches qui seront empilés pour former la structure VCSEL. La seconde partie traite des différentes conditions pour obtenir une source laser monomode. La troisième partie présente les procédés de fabrication qui ont étés mis en place. Notamment de la sous-gravure sélective de la Jonction Tunnel (JT), qui est une technique de confinement originale dans le système GaSb. Celle-ci permet de réduire le diamètre de la JT jusqu'à 6 µm, ce qui est la condition pour obtenir une émission monomode.La dernière partie de ce manuscrit présente les caractérisations menées sur les structures monolithiques à JT sous-gravées. La sous-gravure sélective nous a ainsi permis d'obtenir le premier EP-VCSEL monolithique monomode. Ce composant fonctionne au-delà de la température ambiante et en régime continu. Avec des courants de seuils aussi bas que 1,9 mA et un fonctionnement jusqu'à 70°C. Le développement des structures monolithique à zone active (ZA) en cascade a également permis d'augmenter les puissances optiques en sortie de ces composants. Celles-ci sont passées de 300 µW @ 20°C à 950 µW pour la première structure citée classique et la structure à ZA en cascades respectivementThis thesis deals with study and conception of GaSb-based electrically pumped Vertical Cavity Surface Emitting Lasers (EP-VCSELs) emitting in the mid-infrared range above 2 µm. This VCSELs exhibits suitable characteristics for gas analysis like single-mode emission and a large current tunability without mode-hopping. The objective of this work was to develop such devices. The first part of this work is about properties of the epitaxial stack layers used to form the VCSEL structure. The second parts deal with characteristics and the confinement system to design a single mode cavity. The third part presents manufacturing process which has been set up, like Tunnel Junction (TJ) under-etching, which is an innovate approach on the GaSb system. It allows reducing TJ diameter down to 6 µm, which is a necessary point to demonstrate single-mode operation.The final part of this manuscript presents the characterisations purchased on the under-etched TJ monolithic-VCSELs. Selective under-etching of the TJ allowed the first demonstration of the first single-mode monolithic EP-VCSEL. This device emits around 2.3 µm in continuous regime above room temperature. This device exhibits threshold currents as low as 1.9 mA and operate up to 70°C. The development of bipolar cascaded VCSELs has also allowed increasing the optical power on large diameter multimode, with a maximum output power of 300 µW and 950 µW@20°C for the classic and the bipolar cascaded VCSEL respectively
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Quélard, Didier. "Etude par deformation plastique et frottement interieur de la mobilite des dislocations dans gaas et insb non dopes." Toulouse, INSA, 1987. http://www.theses.fr/1987ISAT0003.
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La premiere partie de ce travail presente l'etude de la deformation plastique par compression uniaxiale de gaas non dope. Des essais de relaxation de la contrainte a differentes temperatures comprises entre 0,35 et 0,54 t::(f) ont permis une premiere mesure de l'energie d'activation de la deformation plastique a differentes contraintes, et une evaluation du mecanisme controlant la deformation. La seconde partie expose les resultats de l'etude par frottement interieur a basse frequence (1 hz) des dislocations dans gaas (0,05 t::(f)t0,66 t::(f)) et insb (0,1 t::(f)0,95 t::(f)) non dopes pour differentes conditions de deformation. Les domaines de frequence et de temperature explores ont permis de mettre en evidence de nouveaux pics de frottement interieur sur insb, qui pourraient etre relies aux mecanismes intrinseques du mouvement des dislocations (vis et 60**(o))
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Mairiaux, Estelle. "Développement d’une nouvelle filière de transistors bipolaires à hétérojonction AlIn(As)Sb/GaInSb en vue applications térahertz." Thesis, Lille 1, 2010. http://www.theses.fr/2010LIL10096/document.
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Les semiconducteurs III-V antimoniés suscitent un intérêt grandissant pour les applications électroniques rapides et faible consommation. Ces matériaux de paramètre de maille supérieur à 6,1 Å se caractérisent par des mobilités élevées et offrent une souplesse inégalée pour l’ingénierie des bandes. En particulier, le composé ternaire GaInSb se pose comme un candidat de choix pour la base des transistors bipolaires à hétérojonction du fait de sa haute mobilité de trous. L’objectif de cette thèse est d’évaluer la faisabilité et les potentialités d’une nouvelle filière de TBH à base d’antimoine en s’appuyant sur des hétérostructures originales AlIn(As)Sb/GaInSb. La réalisation de composants dans ce système moins bien connu que les systèmes plus classiques InP/InGaAs ou InP/GaAsSb a nécessité le développement de briques technologiques propres. L’étude de solutions de gravure pour la réalisation des mesa a notamment été entreprise et a permis d’identifier de nouvelles solutions chimiques adaptées à la gravure sélective de ces matériaux. Une attention particulière a également été portée sur la minimisation des résistivités spécifiques de contact qui a permis de dégager les paramètres critiques à l’obtention de contacts ohmiques de bonne qualité sur les couches en GaInSb de types n et p. La technologie développée a rendu possible la fabrication de dispositifs présentant des fréquences de coupure fT de 52 GHz et fMAX de 48 GHz. La caractérisation électrique précise tant en régime statique que dynamique des composants fabriqués ainsi que l’extraction du modèle petit signal nous ont permis de déterminer les principales limitations de ces dispositifsThe so-called ABCS (antimonide-based compound semiconductor) materials have a great potential for low power, high speed electronics as they have high electron and hole mobilities and provide a unique opportunity for bandgap engineering. The ternary material GaInSb has specifically recently emerged as a good candidate for the base layer of high performance heterojunction bipolar transistors (HBT). The purpose of this work is to demonstrate the feasibility and potentialities of a new antimonide-based HBT structure using AlIn(As)Sb/GaInSb heterojunctions. The fabrication of devices in this material system represents a new technological approach as compared to the conventional InP/GaInAs or InP/GaAsSb HBTs and has necessitated the development of various processing steps. In this study, we have investigated new selective chemical solutions to expose the base and the subcollector surface, as well as for achieving device isolation. High quality and reliable ohmic contacts has also been explored by investigating the factors that influence the specific contact resistivity, thermal stability, and shallowness of the ohmic contacts to n- and p-GaInSb. The fabricated devices demonstrated good microwave behaviour with a current gain cutoff frequency fT of 52 GHz and a maximum oscillation frequency fMAX of 48 GHz. Electrical analysis based on dc and RF measurements and a small signal equivalent circuit model enabled the determination of the limiting factors that need to be addressed for further improvement
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Ma, Shun-kit Martin. "The two gallium vacancy-related defects in undoped gallium antimonide." Click to view the E-thesis via HKUTO, 2004. http://sunzi.lib.hku.hk/hkuto/record/B31319658.
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Ma, Shun-kit Martin, and 馬信傑. "The two gallium vacancy-related defects in undoped gallium antimonide." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31319658.
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Swaminathan, Krishna. "Room-temperature aluminum gallium arsenic antimonide/indium gallium arsenic antimonide heterojunction phototransistors for the 2 micron region." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 83 p, 2009. http://proquest.umi.com/pqdweb?did=1654487611&sid=7&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Conibeer, Gavin John. "Zinc diffusion in tellurium doped gallium antimonide." Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262103.
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Lui, Mei-ki Pattie. "Acceptor defects in P-type gallium antimonide materials." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B31648368.
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Kumta, Prashant Nagesh 1960. "RAPID SOLIDIFICATION PROCESSING OF INDIUM GALLIUM ANTIMONIDE ALLOYS." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276468.
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Solidification from the melt is an essential step in nearly all conventional processes to produce bulk materials for industrial applications. Rapid quenching from the liquid state at cooling rates of 102 to 106K/s or higher has developed into a new technology for processing novel materials. InxGa1 - xSb a ternary III-V compound semiconductor was synthesized by using the rapid spinning cup (RSC) technique. Several compositions of these alloys were batched and cast into ingots in evacuated sealed quartz tubes. These ingots were then melted and ejected onto a rapidly rotating copper disk. This resulted in the generation of flakes or powders depending on the rpm of the disk. Microstructural characterization of the flakes and powders was performed using XRD, SEM and TEM. Efforts were also made to measure the bulk resistivity of the annealed flakes to see the effect of annealing on ordering of the phases.
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Lui, Mei-ki Pattie, and 雷美琪. "Acceptor defects in P-type gallium antimonide materials." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B31648368.
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Mahajumi, Abu Syed. "Type-II gallium antimonide quantum dots in gallium arsenide single junction solar cells." Thesis, Lancaster University, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.658211.
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The novel idea of GaSb quantum dots (QDs)1 quantum rings (QRs) stacked layers single junction solar cells have been investigated for the examination and enhancement of the infrared photo response. Initially the investigation used photoluminescence to probe the optical properties of a type-II material interface between GaSb/GaAs using optimum growth temperature for QDs/QRs with two different growth modes (Stranski-Krastanow (SK) and exchange growth); and two different GaSb deposition thickness (1.5ML and 2.IML). The photoluminescence spectra of the stacked epilayers confirmed that the dominant radiative recombination mechanism was band-to-band in the GaSb QDs/QRs stacked layers. Excellent structural quality is observed in each sample with no threading dislocations (by Transmission Electron Microscopy (TEM)). The composition of the QRs is close to 100 % GaSb with high purity GaAs centres. The ring density per layer is approximately 1010 rings/cm2 with no significant variation in size or density in the separate layers. II Rapid thermal annealing (RTA) has been used to tailor the optical properties of 10-layer stacks of type-II GaSb self-assembled QDs and QRs embedded within GaAs grown by molecular beam epitaxy. An increase in PL emission intensity and a blue shift in peak energy in both types of QD stacks were observed, along with changes in the activation energy for PL quenching. These effects were attributed to Sb-As intermixing and size effects with corresponding changes in the band structure and an increase in the oscillator strength associated with the transformation towards type-I behaviour. It has been concluded that postgrowth rapid thermal annealing can be used to tune the spectral response and control carrier recombination and escape properties of stacked GaSb QD for more effective use in devices such as solar cells and lasers. The final part of the investigation examined the properties of multi-layer QDs/QRs single junction solar cells (SC) to obtain an understanding of the operation and characteristics of the devices. Three kinds of solar cells were fabricated; one is intrinsic layer with ? layers of QDs/QRs, another comprises 10 layers and the final one is control cells (without QDs/QRs).
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Nogaret, Alain. "Etude comparée du transport par effet tunnel résonnant dans les hétérostructures semiconductrices de type I et II en présence de pression hydrostatique et de fort champ magnétique." Toulouse, INSA, 1993. http://www.theses.fr/1993ISAT0037.
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Nous etudions la combinaison de l'effet tunnel resonnant avec l'effet tunnel interbande dans les heterostructures presentant un alignement de type ii. Dans les heterostructures de type i, la quantification magnetique montre qu'un electron avec une importante energie cinetique transverse conserve son energie plutot que son vecteur d'onde transverse, la pression hydrostatique met en evidence un pic de courant extraordinaire que nous attribuons a la formation de niveaux x lies dans les barrieres alas, le calcul clarifie la contribution des modes de phonons lo locaux au courant vallee. Nous exposons les procedes lithographiques que nous avons mis au point pour elaborer le systeme inas/alsb/gasb. Nous soulignons l'importance du choix de l'energie de fermi dans les electrodes et ses multiples consequences sur la forme des caracteristiques courant-tension des heterostructures de type ii. Nos resultats devoilent les mecanismes physiques responsables du courant resonnant interbande et suggerent l'existence d'une bande interdite d'hybridation due au couplage electron-trou. Nous interpretons l'effet tunnel interbande a travers des sous-bandes de trous par les regles de selection usuelles et observons pour la premiere fois la bistabilite intrinseque dans une structure de type ii. Ces resultats nous amenent a comparer les performances de dispositifs electroniques utilisant soit l'effet tunnel resonnant soit l'effet tunnel resonnant interbande
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Walters, Stephanie A. "The metal - n-type gallium antimonide (110) interface : interfacial reactions and Schottky barrier formation." Thesis, Cardiff University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238197.
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Boyle, Jonathan. "Bandstructure engineering of indium arsenide quantum dots in gallium arsenide antimonide barriers for photovoltaic applications." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 92 p, 2008. http://proquest.umi.com/pqdweb?did=1605158181&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Scott, Brian Lee. "Semi-conductor Core Optical Fibers and Fabrication Dependence of the Grain Structure." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/77206.
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The production and fabrication of semi-conductor core optical fibers was shown to be feasible and controllable. This was accomplished through the step sequence of fabrication and characterization of 4 fiber types, an experiment on controlling the grain length in the core and a simple model of the heat transfer during fabrication. Fibers were first made with a silicon core, followed by a phosphorous doped n-type silicon core, then a boron doped p-type silicon core, and a tellurium doped n-type gallium antimonide core. Characterization of the fibers was accomplished with energy dispersive spectroscopy (EDS) for compositional analysis, electron backscatter diffraction (EBSD) for crystal orientation and grain size, optical and electron microscopy for physical fiber quality and optical transmission for core optical quality. A model was developed to relate the heat transfer with the grain structure of the fiber core. All of the fibers fabricated had a polycrystalline core with either no detectable oxygen in the case of the silicon fibers or low amounts of oxygen diffusion into the core as in the case of the GaSb fibers. Fiber lengths ranged from 7 cm for the initial silicon fibers to 60 cm and outside diameters down to 100 µm for n and p type silicon fibers. Core diameters for all fiber types ranged from 10 – 200 µm depending on the fabrication parameters. Lengths of major grains in the core are dependent on the core diameter and the pulling speed. The grain lengths of the major grains in the core generally increase in length with an increase in core diameter. Grain lengths in all fibers are thought to be suitable for use in fabrication of electronic structures in the core region with even the smallest average grain length of around 300 µm. This grain structure satisfies the grain boundary requirements for fabrication of boundary free p-n junctions and other more complicated electronic structures. Small core diameter fibers had better physical quality with fewer cracks and longer continuous length than the larger core fibers.Ph. D.
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Lam, Chi-hung. "Positron annihilation spectroscopy studies of 6H N-type silicon carbide and Zn-doped P-type gallium antimonide." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B36299996.
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Lam, Chi-hung, and 林志雄. "Positron annihilation spectroscopy studies of 6H N-type silicon carbide and Zn-doped P-type gallium antimonide." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B36299996.
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Renard, Charles. "Hétérostructures Antimoniures/Arséniures pour les applications optoélectroniques dans le moyen infrarouge." Phd thesis, Université Paris-Diderot - Paris VII, 2005. http://tel.archives-ouvertes.fr/tel-00124336.
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Les progrès réalisés au cours des trente dernières années dans les domaines de la croissance cristalline et de la technologie des semiconducteurs III-V ont permis aux composants optoélectroniques (lasers, détecteurs) fonctionnant dans la bande 0,4-1,8 µm d'être de nos jours des éléments essentiels pour les télécommunications, le stockage des données ou le domaine médical. Cependant, de nombreuses applications, comme la détection infrarouge, la spectroscopie moléculaire de polluants atmosphériques, nécessitent le développement de lasers et de détecteurs fonctionnant à plus grande longueur d'onde, notamment dans les fenêtres de transparence atmosphériques (3-5 µm et 8-12 µm). La réalisation de ces différents dispositifs est possible en utilisant les hétérostructures mixtes antimoniures/arséniures. Cependant, plusieurs difficultés sont associées à la croissance épitaxiale de ces hétérostructures (désaccords de maille entre les différents matériaux considérés, caractérisation des hétérostructures, incorporation compétitive des différents éléments V As et Sb...).L'objet de cette thèse a consisté, dans un premier temps, à déterminer les conditions de croissance permettant la réalisation des lasers à cascade quantique basés sur le système de matériaux AlAsSb/GaInAs épitaxié sur substrat d'InP et de détecteurs photovoltaïques InAsSb épitaxiés sur substrat de GaSb. Pour ce faire, l'ensemble des paramètres intervenant dans l'incorporation concurrentielle des deux éléments V As et Sb (température, vitesse, nature de l'élément III...) a été étudié. Une procédure de détermination des épaisseurs individuelles et des compositions des hétérostructures GaInAs/AlAsSb, par diffraction de rayons X, basée sur l'utilisation d'un double superréseau a également été proposée. Ce travail a permis de mieux comprendre les phénomènes intervenant aux interfaces selon les conditions de croissance utilisées et d'obtenir ainsi un calibrage rigoureux et reproductible. Des résultats préliminaires satisfaisants ont finalement été obtenus sur les diodes électroluminescentes AlAsSb/GaInAs à cascade quantique sur InP ainsi que sur les détecteurs photovoltaïques InAsSb sur GaSb.
La seconde partie de cette thèse a consisté en l'optimisation des conditions de croissance des hétérostructures (Al,Ga)Sb/InAs épitaxiées sur substrat d'InAs et de GaSb. Dans ce système de matériaux, l'existence d'une ségrégation d'indium aux interfaces AlSb/InAs a pu être mise en évidence par différentes techniques de caractérisation (HRTEM, RHEED, HRXRD). La prise en compte de cette ségrégation a permis d'améliorer les performances des LCQs InAs/AlSb et d'atteindre le fonctionnement à température ambiante. Des résultats prometteurs ont également été obtenus pour des structures détectrices interbandes à cascade GaSb/AlSb/InAs.
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Björk, Magnus. "COMBINED BOILER WITH TPV." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-31488.
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A TPV-system consists of a hot surface emitting heat radiation on a solar cell with a narrow bandgap. A unit consisting of a boiler and a TPV-system has been constructed for testing of the performance of TPV cells. The emitter is heated by a fuel consisting of RME-oil. The radiation is collected and concentrated through two reflecting cones formed like a Faberge-egg, with an edge-type optical filter between the cones. The Faberge-egg is treated with electro-polishing in order to obtain a high reflectance of radiation. The edge filter transmits radiation of short wavelengths towards the solar cells and reflects long wavelengths back to the emitter. This increase the temperature of the emitter to prevent the TPV-cells to be overheated. The construction made was working as expected and can be used for further experiments. The performance of the TPV-cells were however very poor because of a low emitter temperature. The main problem was to obtain a good heat transport from the flame to the emitter. It is required that the emitter temperature is considerably increased for justifying a continued work on TPV-systems in combination with boilers.
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Salesse, Alain. "Contribution à l'étude de la passivation par anodisation en milieu sulfuré non aqueux de semiconducteurs III/V : application à la passivation des antimoniures GaSb et structures à base de GaSb." Montpellier 2, 1995. http://www.theses.fr/1995MON20224.
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Ce travail concerne l'etude de la passivation par anodisation en milieu propanol-2/ acide citrique/thiouree des semiconducteurs iii/v a base d'antimoniure de gallium. La nature de la couche solide anodique a ete determinee au moyen de la spectrometrie de masse (fab), de la sonde ionique et de la spectrometrie de photoelectrons induits par rx (xps). Elle est formee d'un compose de formule chimique gasbt#4#n ou t represente la thiouree. Sa constante dielectrique est de 7,4 et sa conductivite est de quelques 10#-#1#5 ohms#-#1cm#-#1 a l'ambiante. Le champ electrique de claquage est de 2,5 a 3 10#6v. Cm#-#1. L'augmentation de l'intensite de la photoluminescence d'un facteur 2 a 10, sur divers substrats anodises (gasb massif, gasb/gaas et superreseaux gasb/gainsb/gasb 10 periodes), indique une amelioration significative des etats d'interface. La densite moyenne d'etats, mesuree par les methodes de terman et de gray sur des dispositifs mis a base de gasb, est inferieure a 1,5 10#1#2 cm#-#2 a 77k. Les courants de fuites de diodes mesa traitees au moyen de ce procede sont diminues d'un facteur 10 meme apres 6 mois d'exposition a l'air
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Ichas, Valerie. "Étude sous pression des propriétés électroniques et magnétiques de composés de neptunium : NpGa3 et les monopnictures de Np : Net réalisation d'un réfrigérateur d'3He pour la mesure de la résistance électrique en dessous de 1,5K." Université Joseph Fourier (Grenoble ; 1971-2015), 1997. http://www.theses.fr/1997GRE10041.
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La resistance electrique des monopnictures de neptunium npas, npsb, npbi (structure nacl) et de npga#3 (structure aucu#3) a ete mesuree sous haute pression jusqu'a 25gpa et a basse temperature jusqu'a 1. 5k. Dans les monopnictures de np, la mise en ordre antiferromagnetique triple k (3k) produit une forte augmentation de la resistivite a pression ambiante. De plus, dans npsb et npbi, la resistivite montre un comportement semi-conducteur a basse temperature. Sous pression et dans les trois composes, la temperature d'ordre t#o#r#d diminue et la resistance chute discontinuement a basse temperature. La signature de l'ordre 3k est supprimee dans npas et npsb. L'anomalie kondo de la resistance disparait sous pression. La chute de resistance sous pression est interpretee par une modification de la surface de fermi qui coincide probablement avec la suppression de la phase 3k. Nous suggerons que la diminution de t#o#r#d est due a un changement de la surface de fermi en plus d'une legere delocalisation des electrons 5f. Dans npga#3, t#o#r#d augmente de 65k a 1bar jusqu'a 194k a 25gpa. L'anomalie kondo en resistivite est supprimee au dessus de 4gpa. Nos resultats suggerent que deux phases magnetiques sont presentes sous pression. Le comportement sous pression du moment ordonne et de la temperature d'ordre indique une faible delocalisation des electrons 5f. L'augmentation de la temperature d'ordre est expliquee par le renforcement des interactions d'echange indirectes entre ions magnetiques. Parallelement, nous avons developpe un prototype d'un refrigerateur #3he avec pompe a absorbtion par des charbons actifs. Il est destine a mesurer la resistance electrique de composes d'actinides en dessous de 1. 5k et sous haute pression. Le prototype permet d'atteindre des temperatures minimales de 650mk dans les conditions de mesures sous pression et 330mk dans les conditions de mesures a 1bar. Nous avons mesure avec succes la resistance electrique de np#4ru#7ge#6 jusqu'a 350mk et a pression ambiante
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Robinson, Joshua Alexander. "Study of palladium/gallium antimonide reactions and ohmic contacts to n-type gallium antimonide." 2005. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-888/index.html.
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Burke, Robert Redwing Joan M. "MOCVD growth and characterization of gallium nitride and gallium antimonide nanowires." 2008. http://etda.libraries.psu.edu/theses/approved/PSUonlyIndex/ETD-3397/index.html.
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Dutta, Partha Sarathi. "Investigations On Gallium Antimonide : An Optoelectronic Material." Thesis, 1995. http://etd.iisc.ernet.in/handle/2005/2196.
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Hawkins, Brian Edmund. "Metal organic vapor phase epitaxy growth mechanisms of gallium antimonide and compositional grading in psuedomorphic gallium arsenide antimonide films." 2004. http://catalog.hathitrust.org/api/volumes/oclc/61828004.html.
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Yi-ChenLiu and 劉奕辰. "Electrodeposition of Gallium and Gallium Antimonide from 1-Butyl-1-Methylpyrrolidinium Dicyanamide." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/ck5p58.
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GUO, CHIOU TYNG, and 郭秋廷. "Molecular Beam Epitaxial Growth and Characterization Of Gallium Antimonide." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/01572957947030289830.
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碩士國立中山大學
電機工程研究所
83
The molecular beam epitaxy (MBE) growth characteristics of gallium antimonide by using solid Ga(7N) and Sb(6N) as sources in this paper were studied mainly through the growth rate and composition variations of the layers with substrate temperature . We grow the GaSb epitaxial films on GaAs substrates by molec- ular beam epitaxy methods at the temperature range 470C ~ 570C. In order to grow a high quality of GaSb films, the growth mech- anisms are carefully investigated as related to the major fact- ors as (1) substrate temperature (2) beam flux densities (as V/ III ratio ). The films grown by molecular beam epitaxy are characterized by X-ray diffraction, optical microscopy, Cross section transmission electron microscopy(TEM), Hall measure- ments and Raman spectra. From the examinations of the surface morphologies for GaSb heteroepitaxy layers, the optimum growth conditions were obtained as 500C, V/III ratio is about 8 ~ 9. From X-ray diffraction, the quality of the films is best at 500C. It is claer that the lattice constant of epilayer GaSb is nearest close to the lattice constant of the standard wafer from calculating. A high density of dislocations is generated at the GaSb-GaAs interface from Cross-section TEM. From Raman spectrum, we know that LO mode phonon intensity and linewidth is concern about the quality. It is excepetd that based on the growth characteristic studied here, the MBE growth methods are promising also for the growth of terrary compounds, AlGaSb and GaInSb, strained quantum well(AlGaSb/GaSb), quaternary compounds , AlGaInSb, DH lasers. However, further detailed investigations including theoretical considerations are required, to establish the MBE techniques for the growth of antimonide compounds.
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Lin, Hung-En, and 林弘恩. "Magnetotransport in chemically reduced graphene oxide and gallium phosphide antimonide." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/99089623646355400100.
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碩士國立臺灣大學
物理研究所
99
In this thesis, two materials, chemically reduced graphene oxide and GaPSb, were investigated for their magnetotransport behaviors under the influence of a magnetic fields up to 11.6 T at the temperatures between 4.5 K and 80 K. A brief summary of our discovery will be given in the following sections. 1. Magnetotransport in chemically reduced graphene oxide In recent years, transport behavior in chemically reduced graphene oxide (R-GO) has been widely investigated. However similar research in the presence of a magnetic field was rare. In chapter 4, the transport behavior in fully R-GO samples with a magnetic field up to 4 T at selected temperatures between 4.5 K and 80 K was studied. Negative magnetoresistance (NMR) was observed in all our R-GO samples. The magnitude of NMR was found to decrease with the increasing temperature and the increasing thickness of the R-GO film. A Mott hopping behavior, concluded from the data analyzed by using Sivan, Entin-Wohlman, and Imry (SE-WI) model, was found to be the dominant electron conducting mechanism for the NMR phenomenon. The magnetotransport features can be explained by a model based on the spin-coupling effect from vacancy-induced midgap states that facilitate the Mott variable range hopping (VRH) conduction in the presence of an external magnetic field. The origin of the staircase-like NMR revealed on the 3-nm-thick sample is not clear although it was also observed at a lower temperature from the dilute fluorinated graphene. Further investigations are required to elucidate the nature of this unusual behavior. 2. Magnetotransport in gallium phosphide antimonide The second part of this thesis was dedicated to the study of the transport behavior in a GaPSb sample in the presence of a perpendicular magnetic field at low temperatures. The Hall measurement indicated that the carrier concentration was about 1016 cm-3 and electrons were the dominant carriers in our sample. The NMR followed by PMR was observed along with the increase of a magnetic field up to 11.6 T. At the temperature regime between 40 K and 80 K, either three- or two-dimensional Mott VRH model or ES VRH model can be used to describe the electron transport behavior. To elucidate the ambiguity, the magnetoresistance theory in VRH regime was employed to analyze the transport behavior, showing that the transport behavior of the 720-nm-thick GaPSb is consistent with a two-dimensional Mott VRH conductance.
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"Quantum transport in inverted indium arsenide/gallium antimonide composite quantum wells." Thesis, 2010. http://hdl.handle.net/1911/62155.
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We present a comprehensive study of low temperature quantum transport in double gated InAs/GaSb composite quantum wells. Recently, it has been proposed that this system in inverted regime should exhibit the topologically insulating (TI) phase, characterized by an energy gap in the bulk and gapless edge modes, protected from backscattering by time reversal symmetry. We sweep the Fermi level through the bulk mini-gap, observing resistance peaks and finding strong evidence for the existence of the mini-gap; however, the mini-gap does not show insulating behavior, with a residual bulk conductivity which is a few times larger then the expected contribution from the edge. Our data indicate, that bulk conductivity is not an issue of "dirt", which can be improved by simply reducing the amount of disorder, but a fundamental property of strongly coupled electron-hole systems in realistic materials, which must be considered in studies of proposed TI edge modes.
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"Transport Properties of Topological Phases in Broken Gap Indium Arsenide/Gallium Antimonide Based Quantum Wells." Thesis, 2012. http://hdl.handle.net/1911/70295.
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The quantum Spin Hall Insulator (QSHI) is a two-dimensional variant of a novel class of materials characterized by topological order, whose unique properties have recently triggered much interest and excitement in the condensed matter community. Most notably, the topological properties of these systems hold great promise in mitigating the difficult problem of decoherence in implementations of quantum computers. Although QSHI has been theoretically predicted in a few different materials, prior to the work presented in this thesis, only the HgTe/CdTe semiconductor system has shown direct evidence for the existence of this phase. Ideally insulating in the bulk, QSHI is characterized by one-dimensional channels at the sample perimeter, which have a helical property, with carrier spin tied to the carrier direction of motion, and protected from elastic back-scattering by time-reversal symmetry. In this thesis we present low temperature transport measurements, showing strong evidence for the existence of proposed helical edge channels in InAs/CaSb quantum wells, which thus emerge as an important alternate to HgTe/CdTe quantum wells in studies of two-dimensional topological insulators and superconductors. Surprisingly, edge modes persist in spite of comparable bulk conduction of non-trivial origin and show only weak dependence on magnetic field in mesoscopic devices. We elucidate that the seeming independence of edge on bulk transport comes due to the disparity in Fermi wave-vectors between the bulk and the edge, leading to a total internal reflection of the edge modes. Furthermore, low Schottky barrier of this material system and good interface to superconductors allows us to probe topological properties of helical channels in Andreev reflection measurements, opening a promising route towards the realization of topologically superconducting phases hosting exotic Majorana modes.
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Cheng, Yu-Chieh, and 鄭宇傑. "Characterization of Single-layer and Multi-layer Metal Films Contacts on P-Type Gallium Antimonide." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/9896nt.
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碩士國立交通大學
材料科學與工程學系所
105
As the scaling of device continued shrinking, the Si-based complementary metal-oxide-semiconductor (CMOS) has faced difficulties in enhance the device performance due to the physical limitation. For the past few years, the introduction of alternative materials and device structures are expected to improve the device performance. III–V compound semiconductor materials have higher carrier mobility compared with Si, which lead to the higher device performance at low power supply. Among the III–V compound semiconductor materials, GaSb has the bulk hole mobility of ~1000 cm2/Vs, higher than that of most other III–V compounds, as well as a sufficiently large band gap (0.72 eV), which is promising to replace Si as the materials of the transistors. One of the main challenges to achieve the high performance of III-V pMOSFETs is the low-resistance source and drain (S/D) formation. However, the fabrication of high-performance GaSb-based pMOSFETs is difficult owing to the metal/GaSb source/drain contact technologies. Because of the low dopant solubility and high temperature of dopant activation annealing of GaSb, self-aligned metal S/D formation process is necessary for the fabrication process of GaSb-based p-MOSFETs. In this work, the reaction mechanisms and electrical properties of metal films contacts on p-GaSb were characterized. Ni, Co and Ti were used to be materials of the single-layer metal films and the combinations of Ti/Ni and Ni/Ti were used for the multi-layer metal films. The metal-GaSb alloys formed at the interface of the contacts by rapid thermal annealing process (200~600°C / 30s) have been characterized using transmission electron microscopy/energy dispersive spectromter (TEM/EDS), x-ray diffraction (XRD) and atomic force microscopy (AFM). The specific contact resistance of the contacts of metal films on p-GaSb were extracted by circular transmission line model (CTLM). The specific contact resistance increased extremely when the samples were annealed at high temperature due to the phase separation at the interface of contact. The lowest specific contact resistance was measured as 5.3×〖10〗^(-5) Ω-cm2 at the contact of Ti/Ni on p-GaSb annealed at 500°C / 30s compared with other samples. These results indicated that in order to develop the metal-GaSb alloys S/D with low parasitic resistance, the processing temperature should be controlled specifically lower than the temperature of phase separation.
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Wu, Bing-Ruey. "Molecular beam epitaxy of gallium arsenide antimonide-based ultra-high-speed double heterojunction bipolar transistors and light emitting transistors /." 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3250345.
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Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006.Source: Dissertation Abstracts International, Volume: 68-02, Section: B, page: 1204. Adviser: Keh-Yung Cheng. Includes bibliographical references (leaves 83-90) Available on microfilm from Pro Quest Information and Learning.
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Roszmann, Jordan D. "Application of rotating magnetic fields to the travelling heater method growth of GaSb and the synthesis of CdTe." Thesis, 2009. http://hdl.handle.net/1828/1356.
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Understanding and control of the flow structures in metallic fluids is important
for the development of optimal crystal growth processes. One of the techniques used
to control flow structures is the application of a rotating magnetic field (RMF) in
the plane perpendicular to the growth direction, which induces two magnetic body
force components; one in the radial direction and the other one in the circumferential
direction. These two body force components alter the fluid flow in the growth system,
leading to enhanced mixing, flatter growth interface, and more homogeneous crystal
composition. The application of RFM was therefore considered in three separate
projects: 1) the zone refining of cadmium and tellurium, 2) the synthesis of cadmium
telluride (CdTe) by the travelling heater method (THM), and 3) the THM growth of
gallium antimonide (GaSb).
In the zone refining of tellurium, the objective was to enhance the transport
of selenium in the melt since the selenium segregation coefficient is close to unity.
A magnetic field with intensity of 0.6 mT and frequency of 100 Hz was selected
based on the results of earlier numerical simulations. Due to the very low electrical
conductivity of tellurium, the numerical simulations predicted a very small effect of
RMF on selenium transport. The designed zone refining experiments for the tellurium
system have verified this numerical simulation result. On the other hand, cadmium is
an electric conductor, and thus the numerical simulations predicted a notable effect
of RMF. However, experiments on the cadmium system could not be carried out
because of the instability of molten zones caused by cadmium’s very high thermal
conductivity.
The commercial synthesis of CdTe is presently done by THM, which produces
materials with much better stoichiometry than other techniques, but very slow process
speeds make THM very costly. An application of RMF was considered in order
to improve the speed of the process. A 1.3 mT, 0.5 Hz field was applied during the
THM synthesis of CdTe. Under the experimental conditions employed, the examination
of samples has shown that the application of RMF did not increase the maximum
synthesis speed. The use of higher intensity RMF was not possible with the present
system, but it is thought that higher fields might worsen the mixing of Cd and Te to
produce non-stoichiometry.
The objective of the third project was to carry out preliminary THM growth experiments
for GaSb under RMF in order to prepare a basis for future THM growth
experiments aimed at reducing the cost of THM by using higher growth rates and
smaller seeds with tapered ampoules. The substantially redesigned THM furnace permits
rotation of the growth ampoule, better control of the experimental environment,
and a stronger temperature gradient at the growth interface. Two crystals have been
grown at 25 mm diameter with and without the application of a magnetic field of
0.6-mT intensity and 100-Hz frequency. These preliminary experiments have shown
that the system can be used for the planned THM experiments; however, further
experiments are required to attribute any effect to RMF.
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Roszmann, Jordan Douglas. "Simulation and growth of cadmium zinc telluride from small seeds by the travelling heater method." Thesis, 2016. http://hdl.handle.net/1828/7347.
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The semiconducting compounds CdTe and CdZnTe have important applications in high-energy radiation detectors and as substrates for infrared devices. The materials offer large band gaps, high resistivity, and excellent charge transport properties; however all of these properties rely on very precise control of the material composition. Growing bulk crystals by the travelling heater method (THM) offers excellent compositional control and fewer defects compared to gradient freezing, but it is also much slower and more expensive. A particular challenge is the current need to grow new crystals onto existing seeds of similar size and quality.
Simulations and experiments are used in this work to investigate the feasibility of growing these materials by THM without the use of large seed crystals. A new fixed-grid, multiphase finite element model was developed based on the level set method and used to calculate the mass transport regime and interface shapes inside the growth ampoule. The diffusivity of CdTe in liquid tellurium was measured through dissolution experiments, which also served to validate the model. Simulations of tapered THM growth find conditions similar to untapered growth with interface shapes that are sensitive to strong thermosolutal convection. Favourable growth conditions are achievable only if convection can be controlled.
In preliminary experiments, tapered GaSb crystals were successfully grown by THM and large CdTe grains were produced by gradient freezing. Beginning with this seed material, 25 mm diameter CdTe and CdZnTe crystals were grown on 10 mm diameter seeds, and 65 mm diameter CdTe on 25 mm seeds. Unseeded THM growth was also investigated, as well as ampoule rotation and a range of thermal conditions and ampoule surface coatings. Outward growth beyond one or two centimeters was achieved only at small diameters and included secondary grains and twin defects; however, limited outward growth of larger seeds and agreement between experimental and numerical results suggest that tapered growth may be achievable in the future. This would require active temperature control at the base of the crystal and reduction of convection through thermal design or by rotation of the ampoule or applied magnetic fields.Graduate
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jordan.roszmann@gmail.com