Dissertations / Theses on the topic 'III-V compound semiconductor nanostructures'
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Grant, Victoria Anne. "Growth and characterisation of III-V semiconductor nanostructures." Thesis, University of Nottingham, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.490983.
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This thesis describes the growth and characterisation of III-V semiconductor materials and nanostructures. The material was grown by molecular beam epitaxy (MBE) and characterised using a range of techniques including atomic force microscopy (AFM), cross-sectional scanning tunnelling microscopy (XSTM) and x-ray diffraction (XRD).
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Gomes, Rajiv. "Compound III-V semiconductor avalanche photodiodes for X-ray spectroscopy." Thesis, University of Sheffield, 2012. http://etheses.whiterose.ac.uk/2560/.
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Tey, Chun Maw. "Advanced transmission electron microscopy studies of III-V semiconductor nanostructures." Thesis, University of Sheffield, 2006. http://etheses.whiterose.ac.uk/14901/.
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III -V semiconducting materials allow many novel optoelectronic devices, such as light emitting diodes and lasers, to be developed. Furthermore, recent development in crystal growth techniques allows the growth of low-dimensional semiconductor heterostructures. To achieve the best performance, the crystallinity and the growth mechanism of the devices have to be analysed. In this work, a JEOL JEM-2010F field emission gun transmission electron microscope (TEM) is employed to analyse the nanoscale semiconductor structures. Various techniques, such as conventional TEM, scanning TEM, high resolution TEM and energy-filtered TEM were employed to characterize the structural properties of III-V semiconducting materials. In this thesis, advanced TEM analysis on InAs/GaAs quantum dots with InAIAs capping layer, GaInNAs/GaAs quantum wells and annealed low temperature-grown GaAs are presented. The former investigates the impact of varying the thicknesses of InAIAs in the combined two-level InAIAs-InGaAs capping layer on InAs/GaAs quantum dots. Based on the energy-filtered TEM images, the concentration of Al near the apex of the dots is significantly reduced. An increase in the height of the quantum dots has been observed when the thickness of InAIAs capping layer is increased. This is attributed to the suppression of indium atom detachment rate from the InAs dots during the capping process. Effects of growth temperature on the structural properties of 1.6 um GaInNAs/GaAs mUltiple quantum wells were also investigated. TEM studies show that compositional modulations and dislocations occurred in the sample grown at 400°C and possible point defect formation in the sample grown at 350 °C. The photoluminescence intensities for samples grown at 350 and 400°C are degraded dramatically, compared with the sample grown at 375 °C. The effects of low temperature-growth GaAs annealed at different temperatures were systematically investigated by TEM. Along with other collaborative measurements, the arsenic precipitate parameters obtained from TEM images were employed to develop a semi-quantitative model based on Ostwald ripening to explain the precipitate formation. Furthermore, the "two-trap" model successfully explains the anomalous features in the carrier lifetime and resistivity trends in annealed low temperature-grown GaAs.
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Gryczynski, Karol Grzegorz. "Electrostatic Effects in III-V Semiconductor Based Metal-optical Nanostructures." Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc115090/.
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The modification of the band edge or emission energy of semiconductor quantum well light emitters due to image charge induced phenomenon is an emerging field of study. This effect observed in quantum well light emitters is critical for all metal-optics based light emitters including plasmonics, or nanometallic electrode based light emitters. This dissertation presents, for the first time, a systematic study of the image charge effect on semiconductor–metal systems. the necessity of introducing the image charge interactions is demonstrated by experiments and mathematical methods for semiconductor-metal image charge interactions are introduced and developed.
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Lu, Ryan P. "III-V compound semiconductor dopant profiling using scanning spreading resistance microscopy /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2002. http://wwwlib.umi.com/cr/ucsd/fullcit?p3055790.
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Mashigo, Donald. "Raman spectroscopy of ternary III-V semiconducting films." Thesis, Nelson Mandela Metropolitan University, 2009. http://hdl.handle.net/10948/1011.
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The III-V semiconductor compounds (i.e. In Ga As x 1-x , 1 x x InAs Sb - , In Ga Sb x 1-x and Al Ga As x 1-x ) have been studied using room temperature Raman spectroscopy. X-ray diffraction has been used as a complementary characterization technique. In this study all the III-V semiconductor compounds were grown by metal organic chemical vapour deposition (MOCVD) on GaAs and GaSb substrates. The layers were studied with respect to composition, strain variation and critical thickness. Raman spectroscopy has been employed to assess the composition dependence of optical phonons in the layers. The alloy composition was varied, while the thickness was kept constant in order to investigate compositional effects. A significant frequency shift of the phonon modes were observed as the composition changed. The composition dependence of the phonon frequencies were described by linear and polynomial expressions. The results of this study were compared with previous Raman and infrared work on III-V semiconductor compounds. Strain relaxation in InGaAs and InGaSb has been investigated by Raman and X-ray diffraction. Measurements were performed on several series of layers. For each series, the thickness was varied, while keeping the composition constant. For a given composition, the layer thicknesses were such that some layers should be fully strained, some partially relaxed and some fully relaxed. The Raman peak shifts and XRD confirm that a layer grows up to the critical thickness and then releases the strain as the thickness increases. Critical layer thickness values measured in this study were compared with published data, in which various techniques had been used to estimate the critical thickness.
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Jia, Roger (Roger Qingfeng). "Properties of thin film III-V/IV semiconductor alloys and nanostructures." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113928.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2017.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 116-121).
A large amount of research and development has been devoted to engineering materials for the next generation of semiconductor devices with high performance, energy efficiency, and economic viability. To this end, significant efforts have been made to grow semiconductor thin films with the desired properties onto lattice constants with viable, cost effective substrates. Comparatively less effort has been made to explore III-V/IV heterovalent nanostructures and alloys, which may exhibit properties not available in existing materials. The investigation of these structures, grown using MOCVD, is the goal of this thesis and is motivated by two factors: one, that III-V/IV nanostructures should be good thermoelectrics based on the "phonon glass electron crystal" concept, and two, that (GaAs)₁-x(Ge₂)x alloys were observed to exhibit near-infrared room temperature luminescence, a result that can have significant implications for low bandgap optical devices. A survey of various growth conditions was conducted for the growth of the model GaAs/Ge system using MOCVD to gain insight in the epitaxy involving heterovalent materials and to identify structures suitable for investigation for their thermoelectric and optical properties. A significant decrease in the thermal conductivities of GaAs/Ge nanostructures and alloys relative to bulk GaAs and bulk Ge was observed. This reduction can be attributed to the presence of the heterovalent interfaces. The electron mobilities of the structures were determined to be comparable to bulk Ge, indicating minimal disruption to electron transport by the interfaces. A further reduction in thermal conductivity was observed in an (In₀.₁Ga₀.₉As)₀.₈₄(Si0₀.₁Ge₀.₉)₀.₁₆ alloy; the alloy had a thermal conductivity of 4.3 W/m-K, comparable to some state-of-the-art thermoelectric materials. Room temperature photoluminescence measurements of various compositions of (GaAs)₁-x(Ge₂)x alloys revealed a maximum energy transition of 0.8 eV. This bandgap narrowing is the result of composition fluctuations; the fluctuations create regions of lower bandgap, resulting in a weak dependence on luminescence as a function of Ge composition as well as lower bandgap than the homogeneous alloy with the same composition. As silicon was added to the (GaAs)₁-x(Ge₂)x alloy, the bandgap increased despite the composition fluctuations. Based on the results from this work III-V/IV nanostructures show promise for thermoelectric and optical applications.
by Roger Jia.
Ph. D.
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McAdoo, James Alexander. "Factors affecting carrier transport in ultrafast III-V compound semiconductor based photodiodes." W&M ScholarWorks, 2000. https://scholarworks.wm.edu/etd/1539623974.
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This dissertation describes a comparative study conducted on GaAs MSM photodetectors to assess the importance of surface effects on the optical and frequency response characteristics of MSM photodetectors. MSM photodetectors on III-V compound semiconductors are technologically important because of their applications to fiber optic communication systems. While surface effects have been previously ignored, they must be considered in assessing the ultimate performance limits of such devices, especially if nanoscale MSM photodetectors are to be used. A controlled study was carried out in which high quality devices were subjected to surface damage over a known range and the resultant effects of optical and high frequency performance were observed and correlated with the damage.
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Thota, Venkata Ramana Kumar. "Tunable Optical Phenomena and Carrier Recombination Dynamics in III-V Semiconductor Nanostructures." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1451807323.
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Lee, Kyeongkyun. "Modeling and optimization of molecular beam epitaxy for III-V compound semiconductor growth." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/14836.
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Williams, Howard R. "Compound semiconductor material manufacture, process improvement." Thesis, University of South Wales, 2002. https://pure.southwales.ac.uk/en/studentthesis/compound-semiconductor-material-manufacture-process-improvement(d0373158-08d9-4332-9278-f5353203dcd0).html.
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IQE (Europe) Ltd. manufactures group III/V compound semiconductor material structures, using the Metal Organic Vapour Phase Epitaxy process. The manufactured ranges of semi-conducting materials are relative to discrete or multi-compound use of Gallium Arsenide or Indium Phosphide [III/V]. For MOVPE to compete in large-scale markets, the manufacturing process requires transformation into a reliable, repeatable production process. This need is identified within the process scrap percentage of the process when benchmarked against the more mature Si-CVD process. With this wide-ranging product base and different material systems, flexible processes and systems are essential. The negative impact however, of this demanded flexibility is a complex system, resulting in instability. Minor fluctuations in time, flow, pressure, temperature, or composition in the manufacturing process, will lead to characteristic differences in the produced material [product], when comparing the prescribed run to the actual run. The product profile changes very rapidly, correspondingly the failure profile of the process is equally as dynamic, it is essential therefore that the analysis and projected activities and actions can be identified and consolidated in a timely manner. This project evaluates the process used by IQEE to manufacture III/V compound semi-conducting material structures and uses the business performance to identify the process drivers. One year's [1997] business and process information is used for a single iteration of the improvement cycle. These drivers are then utilised as operators and offer the critical weaknesses in the process related to performance blockages. Some of the techniques utilised in the process evaluation and cause derivation; are original contributions specifically derived for use with a multi-platform complex process with multiple cause and effect operators. A double reporting FMEA contributes a differing rank for like machines running differing products, offering a machine specific failure profile. A novel composite of P-diagram and process flow techniques enables determination of activity influences confirming the key failure mechanism as previously identified by the business risk analysis. This project concludes by nominating the key failure mechanism accounting for 41% of the approximate 50% scrap figure identified again within the business risk analysis. The effects attributed to this failure mechanism are 2- dimensionally analysed utilising an original double operating FMEA, plotting effect to effect for the individual causes, offering a prioritised list of failure categories. The highest priority failure mode is addressed by an equipment design exercise, resulting in an overall 10% sales potential recontribution.
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Norman, A. G. "TEM/TED studies of epitaxial layers of ternary and quaternary III-V compound semiconductor alloys." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233511.
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Cheng, Cheng-Wei Ph D. Massachusetts Institute of Technology. "In-situ deposition of high-k dielectrics on III-V compound semiconductor in MOCVD system." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/59216.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2010.Includes bibliographical references (p. 164-168).
In situ deposition of high-k materials to passivate the GaAs in metal organic chemical vapor deposition (MOCVD) system was well demonstrated. Both atomic layer deposition (ALD) and chemical vapor deposition (CVD) methods were applied in this research. The CVD aluminum nitride (AIN) was first selected to be in situ deposited on GaAs surface by using trimethlyaluminum(TMA) and dimethylhydrazine (DMHy). However, the frequency dispersion of Capacitance-Voltage (C-V) curves for in situ AIN/GaAs samples are always large because of the existence of high interfacial defect state density (Dit) due to the nitridization of the GaAs surface during the AIN deposition. In order to avoid the surface reaction, in situ ALD of aluminum oxide (A1₂O₃) on GaAs in MOCVD system was proposed. Isopropanol (IPA) was chosen as the oxygen source for A1₂O₃ ALD and the mechanism was investigated. Pure A120 3 thin film was obtained and no arsenic or gallium oxide was observed at the interface. Both frequency dispersion of C-V curve and the Di, of oxide/p-GaAs interface are low for this process. In situ CVD A1₂O₃ on GaAs was also performed. Gallium oxide (Ga₂O₃) was observed at the interface. The Ga₂O₃ was enriched in the A1₂O₃ above the interface during the deposition process and a possible mechanism was proposed. This layer reduces the frequency dispersion of the C-V characteristics and lowers the Dit of n-type GaAs sample. After the in situ method had been successfully established, ex situ experiments was also performed to compare the results with in situ process in the same MOCVD system. Annealing native oxide covered GaAs samples in Arsine (AsH 3) prior to ALD A1₂O₃ results in C-V characteristics of the treated samples that resemble the superior C-V characteristics of p-type GaAs. Besides, both TMA and IPA show self-cleaning effect on removing the native oxide in ex situ process. The discrepancy in the C-V characteristics was observed in in situ p- and n-type GaAs samples. Finally, the entire Dit energy distributions of interfaces from different processes were determined by conductance frequency method with temperature-variation C-V measurement. The existence of Ga₂O₃ at interface was found to be the possible source to lower the density of mid-gap defect state. From the C-V simulation, the mid-gap defect states are acceptor-like (Gallium Vacancies) and the source to cause high frequency dispersion of the C-V curves for n-type substrate. The relation between the interfacial defect state distribution and the processes was correlated.
by Cheng-Wei Cheng.
Ph.D.
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Hetherington, Dale Laird. "III-V compound semiconductor integrated charge storage structures for dynamic and non-volatile memory elements." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/186112.
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This thesis presents an investigation into a novel group of GaAs charge storage devices. These devices, which are an integration of bipolar and junction field effect transistor structures were conceived, designed, fabricated, and tested within this study. The purpose was to analyse new types of charge storage devices, which are suitable for fabrication and lead to the development of dynamic and nonvolatile memories in III-V compound semiconductors. Currently, III-V semiconductor storage devices consist only of capacitors, where data is destroyed during reading and electrical erasure is difficult. In this work, four devices types were demonstrated that exhibit nondestructive reading, and three of the prototypes can be electrically erased. All types use the junction field effect transistor (JFET) for charge sensing, with each having different bipolar or epitaxial layer structure controlling the junction gate. The bottom epitaxial layer in each case served as the JFET channel. Two of the device types have three alternately doped layers, while the remaining two have four alternately doped layers. In all cases, removal of majority carriers from the middle layers constitutes stored charge. The missing carriers deplete the current carrying a region of the JFET channel. Drain current of the JFET becomes an indicator of stored charge. The basic function of each JFET memory element type is independent of interchanging n- and p- type doping within the structure type. Some performance advantage can be realized, however, by sensing with an n-type channel as compared to p- type due to increased carrier mobility. All device types exhibit storage time characteristics of order ten seconds. Devices are constructed in epitaxial layers grown by molecular beam epitaxy (MBE) reactors. The design of the epitaxial layers is an intrinsic part, together with the electrical design, of the storage device concept. These concepts are implemented first with photolithography masks which are used in device fabrication. The fabrication methods employ wet chemical etching and ohmic metal liftoff techniques. Electrical dc and charge retention time characteristics along with functionality read/write operations for the memory element group are measured using commercial electronic test equipment.
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Al, Zoubi Tariq [Verfasser]. "Molecular Beam Epitaxial Growth of III-V Semiconductor Nanostructures on Silicon Substrates / Tariq Al Zoubi." Kassel : Universitätsbibliothek Kassel, 2013. http://d-nb.info/1043814876/34.
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Gonzalez, Maria. "Electronic Defects of III-V Compound Semiconductor Materials Grown on Metamorphic SiGe Substrates for Photovoltaic Applications." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1250703650.
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Robert, Cédric. "Study of III-V nanostructures on GaP for lasing emission on Si." Thesis, Rennes, INSA, 2013. http://www.theses.fr/2013ISAR1913/document.
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Ce travail de thèse porte sur l’étude de nanostructures semi- conductrices III-V pour le développement d’émetteurs laser sur silicium dans une approche pseudomorphique. Une croissance en accord de maille d’alliages à base de GaP ou plus précisément de nitrures dilués GaPN doit garantir une faible densité de défauts cristallins. Le modèle des liaisons fortes à base étendue est tout d’abord présenté afin de simuler les propriétés électroniques et optiques de structures semi-conductrices sur substrats de GaP ou Si. Les propriétés des alliages massifs GaPN et GaAsPN sont étudiées par des expériences de photoluminescence continue en fonction de la température et de photoluminescence résolue en temps. Les potentialités des puits quantiques GaAsPN/GaP en tant que zone active sont étudiées théoriquement par le modèle des liaisons fortes et expérimentalement en spectroscopie de photoluminescence en température et résolue en temps. Les effets de désordre engendrés par l’incorporation d’azote sont notamment mis en évidence. L’alliage AlGaP est ensuite proposé pour les couches de confinement optique des structures laser. Un contraste d’indice optique entre AlGaP et GaP est mesuré par ellipsométrie spectroscopique. Ce contraste doit permettre un confinement efficace du mode optique. Le problème de l’alignement des bandes en présence d’aluminium est ensuite évoqué. L’utilisation de l’alliage quaternaire GaAsPN est proposée pour résoudre ce problème. Enfin, les boites quantiques InGaAs/GaP sont étudiées en tant qu’alternative aux puits quantiques GaAsPN/GaP dans la zone active. Une forte densité de boites quantiques et une émission de photoluminescence à température ambiante sont ainsi obtenues pour ce système. Les états électroniques des boîtes quantiques sont simulés par la technique des liaisons fortes et la méthode k.p. La photoluminescence résolue en temps couplée à des expériences de photoluminescence continue sous pression hydrostatique, permet de montrer que la transition fondamentale de ces boîtes implique majoritairement des états de conduction de type XThis PhD work focuses on the study of III-V semiconductor nanostructures for the development of laser on Si substrate in a pseudomorphic approach. GaP-based alloys and more specifically dilute nitride GaPN-based alloys are expected to guarantee a low density of crystalline defects through a perfect lattice-matched growth. An extended tight-binding model is first presented to deal with the theoretical challenges for the simulation of electronic and optical properties of semiconductor structures grown on GaP or Si substrate. The optical properties of bulk GaPN and GaAsPN alloys are then studied through temperature dependent continuous wave photoluminescence and time-resolved photoluminescence experiments. The potential of GaAsPN/GaP quantum wells as a laser active zone is discussed in the framework of both theoretical simulations (with the tight-binding model) and experimental studies (with temperature dependent and time-resolved photoluminescence). In particular, the N-induced disorder effects are highlighted. The AlGaP alloy is then proposed as a candidate for the cladding layers. A significant refractive index contrast between AlGaP and GaP is measured by spectroscopic ellipsometry which may lead to a good confinement of the optical mode in a laser structure. The issue of band alignment is highlighted. Solutions based on the quaternary GaAsPN alloy are proposed. Finally, the InGaAs/GaP quantum dots are studied as an alternative to GaAsPN/GaP quantum wells for the active zone. The growth of a high quantum dot density and room temperature photoluminescence are achieved. The electronic band structure is studied by time-resolved photoluminescence and pressure dependent photoluminescence as well as tight-binding and k.p simulations. It demonstrates that the ground optical transition involves mainly X-conduction states
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Sieg, Robert M. "Critical issues in III-V compound semiconductor epitaxy on group IV (Si,Ge) substrates for optoelectronic applications /." The Ohio State University, 1998. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487953567771998.
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Lidsky, David. "Design, Fabrication and Characterization of a GaAs/InxGa1-xAs/GaAs Heterojunction Bipolar Transistor." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/52591.
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Designs for PnP GaAs/InxGa1-xAs/GaAs heterojunction bipolar transistors (HBTs) are proposed and simulated with the aid of commercial software. Band diagrams, Gummel plots and common emitter characteristics are shown for the specific case of x=1, x=0.7, and x linearly graded from 0.75 to 0.7. Of the three designs, it is found that the linearly graded case has the lowest leakage current and the highest current gain. IV curves for all four possible classes of InAs/GaAs heterojunction (nN, nP, pN, pP) are calculated. A pN heterojunction is fabricated and characterized. In spite of the 7% lattice mismatch between InAs and GaAs, the diode has an ideality factor of 1.26 over three decades in the forward direction. In the reverse direction, the leakage current grows exponentially with the magnitude of the bias, and shows an effective ideality factor of 3.17, in stark disagreement with simulation. IV curves are taken over a temperature range of 105 K to 405 and activation energies are extracted. For benchmarking the device processing and the characterization apparatus, a conventional GaAs homojunction diode was fabricated and characterized, showing current rectification ratio of 109 between plus one volt and minus one volt. Because the PnP material for the optimal HBT design was not available, an Npn GaAs/InAs/InAs HBT structure was processed, characterized, and analyzed. The Npn device fails in both theory and in practice; however, by making a real structure, valuable lessons were learned for crystal growth, mask design, processing, and metal contacts.Master of Science
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Wipatawit, Praphaphan. "Studies of magnetoresistance and Hall sensors in semiconductors." Thesis, University of Oxford, 2006. http://ora.ox.ac.uk/objects/uuid:58faf6f4-debb-4695-8909-fca7cbf310a2.
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The design, fabrication and performance of an Extraordinary Magnetoresistance (EMR) and a Vertical Mesa Hall Sensor (VMHS) are studied. EMR devices have been fabricated from a 2DEG InAs/GaSb structures which exhibit a low carrier density and high mobility that achieve the best performance. The general electrical magneto-transport properties are given. The experiments investigate mainly different metallic patterns, which are Rectangular, Triangular and Tip pattern between 4-300 K. Probe configurations and the enhancement of relative size of metallic patterns are described. EMR effect is due to current deflection around the metal-semiconductor interface. The results are metallic pattern dependent. Using finite element analysis, good agreement between experimental and theoretical results was found. The best performance sensor is a symmetrical metallic Tip pattern. It is enhanced by the length of the Tip’s point and the large metallic area. This pattern when combines with an asymmetrical probe configuration, exhibits the highest EMR of 900% at –0.275T measured by inner probes and the best sensitivity of 54Ω/T at room temperature. The second study presents in-plane Hall effect sensors made from InSb. A simple device geometry has been used in which current flows in a plane perpendicular to the device surface. Device sensitivity depends on its geometry and a series of different contacts are used to investigate the geometry of the current flow distribution. The structures produced are only sensitive to the presence of one in-plane field component, and they also demonstrate good angular selectivity. Multi-electrodes were used to investigate biasing current from both mesa and substrate condition. We are able to examine the Hall voltage as a function of contact positions and also to create multiple VMHS. Offset reduction of devices has been achieved by moving the ground contacts to re-balance the current distribution under the mesa surface.
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Blot, Xavier. "Réalisation, caractérisation et modélisation de collages de matériaux III-V pour cellules photovoltaïques à concentration." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAT108/document.
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La production d'énergie photovoltaïque est une option d'avenir pour répondre au développement économique de notre société tout en réduisant notre impact sur l'environnement. Mais pour devenir compétitive, cette filière doit améliorer le rendement des cellules solaires. Une technologie d'avenir consiste à combiner différents matériaux via une croissance par épitaxie et l'usage du collage direct. Cette thèse, financée par SOITEC, vise au développement du collage d'arseniure de gallium (GaAs) sur le phosphure d'indium (InP) pour la cellule SmartCell. L'objectif est d'optimiser son comportement électrique via un modèle numérique prenant en compte son état physico-chimique. Nous présentons d'abord un ensemble d'outils de caractérisations électriques pour réaliser une mesure I(V) précises de l'interface de collage. En fonction des cas, nous détaillons des contacts métalliques adaptés pour améliorer cette caractérisation. Une étude détaillée de l'hétérostructure GaAs/InP et des homostructures GaAs/GaAs et InP/InP amène ensuite à une compréhension de leur mécanisme de collage. Après recuit thermique, le procédé de collage hydrophile engendre des oxydes d'interfaces qui se résorbent dans le cas de l'InP et se fragmentent pour le GaAs. A paramètres constants, les empilements obtenus sont meilleurs que ceux de l'état de l'art au niveau électrique et mécanique. Nous poursuivons avec des propositions de procédés innovants pour maitriser l'oxyde d'interface et optimiser l'hétérostructure. Parmi ces options nous validons l'approche avec exposition ozone qui vise à générer sélectivement un oxyde avant mise en contact. L'empilement obtenu affiche une résistance proche de nos mesures de référence et a un fort potentiel. Enfin l'étude se conclue sur la présentation d'un modèle numérique inédit reliant procédé de collage, état d'interface et comportement électrique. A recuit donné, l'interface est hétérogène avec une zone reconstruite (conduction thermo-électronique) et une zone avec oxyde (conduction tunnel). Ces régions s'activent préférentiellement en fonction de la température de fonctionnement. Elles sont pondérés par un critère qui détermine le niveau de reconstruction du collage et qui sera utile pour de futurs développements de l'applicationThe solar photovoltaic is a promising way to support our economical growth while it can reduce the environmental impact of our society. But, to be truly competitive, the sector has to develop more efficient solar cells. An interesting option aims at combining different materials either by epitaxy growth and direct bonding. The Ph.D. was funded by the SOITEC company with the goal to develop the bonding of the gallium arsenide (GaAs) on the indium phosphide (InP) for the SmartCell architecture. We had to optimize its electrical behavior with a numerical model taking into account the bonding interface state. We introduce the study with a wide range of I(V) tools to precisely characterize the bonding interface. Depending on the case, we detail suitable metal contacts to improve the test. A study in deep of the GaAs/InP heterostructure and the GaAs/GaAs and the InP/InP homostructures leads to a better understanding of the bonding mechanisms. After a thermal annealing, the hydrophilic bonding process generates oxyde compounds at the interface which are absorbed in the InP case and are fragmented in the GaAs case. For given parameters, our stacks are electrically and mechanically better than the state of the art. Then we propose innovative processes to control the interface oxyde and thus optimize the heterostructure. Among them, we validate a new approach with ozone exposure that selectively generates an oxyde prior to bonding. The interface resistance of the stack is therefore closed to our best results and has great potentials. To conclude, the study focuses on a novel numerical model connecting the bonding process, the interface state and the electrical behavior. For a given annealing, the interface is heterogenous with reconstructed areas (thermionic conduction) and oxyde areas (tunnel conduction). These regions are preferentially activated as a function of the operating temperature. They are weighted by a criteria determining the level of the bonding reconstruction which will be useful for the future developments of the application
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Briere, Gauthier. "Réalisation de méta-optiques à base de matériaux semi-conducteurs III-V pour des applications dans le visible." Thesis, Université Côte d'Azur (ComUE), 2019. http://www.theses.fr/2019AZUR4075.
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Depuis de récentes années de nouveaux composants optiques ont fait leur apparition. Ces composants connus sous les noms de « Méta-optiques » ou encore « Métasurfaces », rendent possible le contrôle et la mise en forme du front d’onde de la lumière permettant alors de mettre en forme n’importe quel faisceau incident et ainsi créer des fonctionnalités optiques classiques telles que focaliser ou dévier la lumière, ou alors des fonctionnalités aux propriétés surprenantes telle que la réalisation de métahologramme dépendant en polarisation. En effet, grâce à l’arrangement périodique de résonateurs de dimensions géométriques sous-longueur d’onde, il est alors possible d’obtenir un contrôle local arbitraire du faisceau incident. Néanmoins, même si de nombreuses applications ont pu être démontré dans la communauté, seuls quelques matériaux se retrouvent être compatibles pour le développement industriel de ces composants. De plus, afin de passer de composant passif à actif, pour la réalisation de composant dynamique, il est nécessaire de passer de matériau diélectrique à matériau semi-conducteur. C’est pourquoi dans ces travaux, nous nous sommes intéressés à l’utilisation d’un matériau semi-conducteur qui est le Nitrure de Gallium pour la réalisation de composants métasurfaciques. Nous présentons alors dans un premier temps une étude numérique des nanostructures utilisées lors de ces travaux. Puis nous montrons comment est réalisée la conception de nos méta-optiques en présentant la méthode de design et les procédés de nanofabrications employés, notamment une nouvelle technique de gravure, compatible uniquement avec les matériaux cristallins et préservant leurs propriétés optiques. Nous exposons ensuite différentes applications où nos composants sont utilisés telles que : la réalisation de métalentilles de large ouverture numérique et de large surface, l’optimisation de réseaux métasurfaciques permettant d’atteindre des efficacités de diffraction supérieur à 80% ou encore la réalisation expérimentale de méta-hologramme permettant de conserver l’information du moment angulaire orbitale du faisceau incidentIn the past years, new optical components have appeared. These components, known as "meta-optics" or "metasurfaces", made it possible to control and to shape the wavefront of the light. This allows the control of any incident beam and the creation of conventional optical functionalities, such as focusing or deflecting the light, or functionalities with additional features such as the possibility of creating polarization-dependent meta-holograms. Indeed, thanks to the periodic arrangement of resonators with sub-wavelength geometric dimensions, it is possible to obtain an arbitrary local control of the incident beam. Nevertheless, even though many applications have been demonstrated in the community, only a few materials are found to be compatible for the industrial development of these components. In addition, in order to pass from passive to active components for the fabrication of dynamic devices, it is necessary to switch from dielectric materials to semiconductor materials. For these reasons, we are interested in the use of a semiconductor material, Gallium Nitride, for the development of metasurface components. We first present a numerical study of the nanostructures used during this work. Then, we show how the design of our meta-optics is done by presenting the numerical conception method and nanofabrication processes used, which includes a new etching technique compatible only with crystalline materials while preserving their optical properties. Finally, we suggest different applications where our components can be used, such as: the development of metalenses with high numerical aperture and large surface; the optimization of metasurface high contrast gratings allowing to reach diffraction efficiencies higher than 80%; or the fabrication of meta-holograms preserving the information of the orbital angular momentum of the incident beam
23
Wu, Xiaoyue. "Simulation Study of Epitaxially Regrown Vertical-Cavity Surface-Emitting Lasers." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-52896.
Full textAbstract:
The vertical-cavity surface-emitting laser or VCSEL is a special type of diode laser, which has established itself in optoelectronic applications asa low-cost, high-quality miniaturized light source. The development of VCSELs can be largely promoted with support from computer simulations. In this study, we have used such simulations, on one hand to understand and improve the VCSEL performance, and on the other hand to prepare for analyzing new device concepts such as transistor-VCSELs. This thesis starts with a background introduction to the principle idea of VCSELs and then states the significance of this simulation work.Then it briefly introduces the previously used simulation workbench Sentaurus and explains the mathematical approach and the computation methods of the finally chosen simulator PICS3D. The case study of a fabricated and characterized epitaxially regrown VCSEL is the major component of this work. First the device configuration is demonstrated with detailed discussion on several design features. Second the physical models of electrical, optical and thermal phenomena along with their key parameters are presented and so are the advanced models for the active region. The main results of simulation, including steady-state characteristics and small-signal modulation, show good agreement with the experimental results and reveal some imperfections of the device design and processing, such as the overestimated stability of the regrown junction and the variation of cavity length caused by over-etch. This work is also treated as an evaluation of the simulator PICS3D, and two problems are identified: one is the troublesome way to construct a 3D device by coupling several 2D layer structures together, requiring the mesh for each layer structure to be compatible; the other would be the tricky boundary setting for the adopted method, Effective Index Method (EIM), for the transverse field calculation when only a weak index guiding effect exits in the cavity. Finally, we summarize this work and suggest some tasks for further simulations.
24
Gillardin, Gérard. "Mise au point d'un appareillage de photoluminescence a haute resolution spatiale : application a l'etude des semiconducteurs et dispositifs electroniques iii-v." Clermont-Ferrand 2, 1988. http://www.theses.fr/1988CLF2D216.
Full textAbstract:
Description du dispositif permettant d'analyser des plaques de 2**(") de diametre a 1ok, avec de hautes resolutions laterales (20 et 1mu m), eventuellement a diverses energies. Realisation de cartographies a 300 et 10k: tres bonne correlation entre intensite de photoluminescence et defauts cristallins et chimiques; correspondance avec des mesures de resistivite electrique. Mise au point d'une procedure de qualification de l'homogeneite microscopique de gaas semi-isolant. Possibilite de prevoir la dispersion des tensions de seuil de transistors fet d'apres l'analyse du support de defaut, donc de classer et choisir les supports pour la realisation de circuits integres
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Widmann, Frédéric. "Epitaxie par jets moléculaires de GaN, AlN, InN et leurs alliages : physique de la croissance et réalisation de nanostructures." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10234.
Full textAbstract:
Ce travail a porte sur la croissance epitaxiale des nitrures d'elements iii gan, aln, et inn, en utilisant l'epitaxie par jets moleculaires assistee par plasma d'azote. Nous avons optimise les premiers stades de la croissance de gan ou aln sur substrat al#2o#3 (0001). Le processus utilise consiste a nitrurer la surface du substrat a l'aide du plasma d'azote, afin de la transformer en aln, puis a faire croitre une couche tampon d'aln ou de gan a basse temperature, avant de reprendre la croissance de gan ou aln a haute temperature (680 a 750c). Nous avons en particulier etudie les proprietes d'une couche de gan en fonction de la temperature a laquelle est realisee l'etape de nitruration. Lorsque les conditions de demarrage de la croissance sont optimisees, nous avons pu observer des oscillations de rheed pendant la croissance de la couche de gan. Nous avons etudie l'effet du rapport v/iii sur la morphologie de surface et les proprietes optiques et structurales de cette couche. Nous avons propose l'utilisation de l'indium en tant que surfactant pour ameliorer ces proprietes. Nous avons ensuite aborde la realisation de superreseaux gan/aln dont nous avons optimise les interfaces. Les mecanismes de relaxation des contraintes de aln sur gan et gan sur aln ont ete etudies. Nous avons egalement elabore les alliages algan et ingan, comme barrieres quantiques dans les heterostructures. Nous avons montre que la relaxation elastique des contraintes de gan en epitaxie sur aln donne lieu a la formation d'ilots de tailles nanometriques, qui se comportent comme des boites quantiques. Leur densite et leur taille dependent de la temperature de croissance, et des conditions de murissement apres croissance. Les proprietes optiques de ces ilots sont gouvernees a la fois par les effets de confinement quantique et par le fort champ piezo-electrique induit par la contrainte dans les ilots.
26
Ruterana, Pierre. "Structure des interfaces, etude par microscopie electronique en transmission, application : materiaux semiconduteurs iii-v et multicouches pour optiques dans le domaine des rayons x mous." Caen, 1987. http://www.theses.fr/1987CAEN2032.
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Nous avons surtout utilise le mode "haute resolution" sur un microscope a 200kv. La resolution obtenue etait de 2. 4 a. La technique de peparation d'echantillons que nous avons mise au point pour l'etude du procede de passivation (si::(3)n::(4)/gaas) nous a permis de caracteriser dans de tres bonnes conditions les multicouches pour rayons x mous et les heterostructures de croissance epitaxiale. Ce travail fut un suivi des procedes en conjugaison avec d'autres techniques de caracterisation. La comparaison des resultats de ces diverses techniques nous a permis d'apprehender la chimie et la physique des interfaces dans les materiaux etudies
27
Karraï, Khaled. "Etude de propriétés magnéto-optiques des hétérostructures de semiconducteurs III-V par spectroscopie submillimétrique." Grenoble 1, 1987. http://www.theses.fr/1987GRE10127.
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Interpretation des resultats experimentaux par un modele de transmission optique en presence de champ magnetique externe, developpe dans le formalisme de la fonction reponse; mise en evidence de l'absence d'interaction electron-phonon to etrange et d'une interpretation satisfaisante sans recours a l'interaction electron-phonon lo, indiquant l'importance de l'effet ecran dans la theorie de l'effet polaron resonnant. Etude de l'interaction spin-orbite induite par le champ electrique existant a l'interface; calcul des regles de selection des transitions entre niveaux de landau dans les differentes configurations magnetooptiques, differences par rapport aux semiconducteurs massifs
28
Shen, Jianyun. "Thermodynamique des systèmes III-V, As-Ga-In et Al-As et analyse de leur épitaxie par jets moléculaires." Grenoble INPG, 1989. http://www.theses.fr/1989INPG0087.
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Diagramme de phase et donnees thermodynamiques du systeme ternaire as-ga-in sont optimises a partir des valeurs experimentales disponsibles. Etude de l'influence de l'energie elastique sur le diagramme de phase. Analyse thermodynamique de l'epitaxie par jets moleculaires des multicouches in#1##yga#yas
29
Marzin, Jean-Yves. "Effets des deformations sur les proprietes optiques des super-reseaux contraints a base de semi-conducteurs iii-v." Paris 7, 1987. http://www.theses.fr/1987PA077132.
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Etude, par photoluminescence, spectrometrie d'excitation et absorption optique, de plusieurs systemes contraints et en particulier du systeme in::(0,15)ga::(0,85)as/gaas sur gaas; modifications de la structure de bande dues aux contraintes natives. Identification des transitions optiques; bon accord avec un modele de fonctions enveloppes incluant les effets des contraintes. Estimation des discontinuite de bandes; configuration des bandes de valence. Etude de systemes fortement contraintes sur l'exemple de inas/gaas; transitions associees a la presence de monocouche(s) de inas dans une matrice gaas; effets lies a la segregation de in en surface et au passage d'un mode de croissance 2d a un mode 3d
30
Erman, Marko. "L'éllipsométrie spectroscopique à haute résolution latérale : modélisation, application aux surfaces, interfaces et puits quantiques dans le matériaux semi-conducteur III-V." Paris 6, 1986. http://www.theses.fr/1986PA066400.
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Etude théorique et expérimentale de l'application de la méthode aux semi-conducteurs III-V et en particulier à l'analyse des interfaces. Etude des systèmes GaAlAs/GaAs et GaInAs/InP. Détermination simultanée de l'épaisseur des couches et de l'énergie de localisation pour les différentes transitions optiques, dans le cas de puits quantiques et de super-réseaux; effets dus au couplage entre les puits quantiques. Obtention de cartographies avec une résolution optique de 10mu m. Le traitement théorique des images ellipsométriques est base sur le concept de trajectoires.
31
BENDRAOUI, ABDELLATIF. "Traitements chimiques et thermiques de composes semi-conducteurs iii-v a base de in, ga, as, p en vue d'une reprise d'epitaxie." Clermont-Ferrand 2, 1989. http://www.theses.fr/1989CLF21151.
Full textAbstract:
L'etat de surface des semiconducteurs iii-v avant la reprise d'epitaxie conditionne les proprietes electroniques et la stabilite des composants realises. Mise en evidence de l'aspect dynamique de stabilisation des composes iii-v a base de in, ga, p et as sous hydrures. Developpement d'une methode originale de stabilisation statique de ces composes a base de chlorures d'in. Analyse des resultats experimentaux et interpretation en utilisant des modeles theoriques bases sur la thermodynamique statistique
32
Moroni, Didier. "Etude des proprietes optiques de semi-conducteurs composes iii-v et de puits quantiques par photoluminescence et excitation de la photoluminescence." Paris 6, 1987. http://www.theses.fr/1987PA066540.
Full textAbstract:
Identification des types de recombinaison entre 2 et 300k dans les couches epaisses de gainas et gainp epitaxiees sur leur support respectif inp et gaas. Etude de l'origine de la luminescence et variation en fonction de l'epaisseur du taux de capture des porteurs de la barriere dans les puits quantiques ingaas/inp. Determination du coefficient d'interdiffusion de al et ga aux interfaces dans les puits quantiques gaas/gaalas
33
Perraud, Simon. "Etude de puits quantiques semiconducteurs par microscopie et spectroscopie à effet tunnel." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2007. http://tel.archives-ouvertes.fr/tel-00606632.
Full textAbstract:
Des puits quantiques à base d'hétérostructures In0.53 Ga0.47 As/In0.52 Al0.48 As, fabriqués par épitaxie par jets moléculaires sur substrats InP(111)A, sont étudiés par microscopie et spectroscopie à effet tunnel à basse température et sous ultra-vide. La première partie est consacrée à une étude de la surface épitaxiée (111)A de In0.53 Ga0.47 As de type n. Il est découvert que le niveau de Fermi de surface est positionné dans la bande de conduction, à proximité du niveau de Fermi de volume, et peut être partiellement contrôlé en variant la concentration d'impuretés de type n dans le volume. Ce résultat est confirmé en déterminant la relation de dispersion de la bande de conduction en surface. Un tel dépiégeage partiel du niveau de Fermi de surface indique que la densité d'états de surface accepteurs est faible. Il est proposé que ces états proviennent de défauts ponctuels natifs localisés à la surface. La deuxième partie, basée sur les résultats obtenus dans la première partie, est consacrée à une étude de puits quantiques In0.53 Ga0.47 As de surface, déposés sur des barrières In0.52 Al0.48 As selon la direction (111)A. Les mesures sont conduites sur la surface épitaxiée (111)A du puits quantique In0.53 Ga0.47 As, de manière à pouvoir sonder à l'échelle du nanomètre la distribution de densité locale d'états électroniques dans le plan du puits quantique. Il est confirmé que des sous-bandes électroniques sont formées dans le puits quantique, et que la concentration d'électrons dans le puits peut être contrôlée du fait du dépiégeage partiel du niveau de Fermi de surface. Il est découvert qu'un phénomène de percolation d'états localisés survient dans la queue de chaque sous-bande, ce qui indique la présence d'un potentiel désordonné dans le puits quantique. Les seuils de percolation sont déterminés en utilisant un modèle semi-classique. L'origine du potentiel désordonné est attribuée à une distribution aléatoire des défauts ponctuels natifs à la surface du puits quantique. Il est également découvert qu'un état lié apparaît au bas de chaque sous-bande à proximité d'un défaut ponctuel natif de type donneur. L'énergie de liaison et le rayon de Bohr des états liés peuvent être directement déterminés. De plus, il est démontré que l'énergie de liaison et le rayon de Bohr sont fonctions de l'épaisseur du puits quantique, en accord quantitatif avec des calculs variationnels d'impuretés dans le modèle de l'atome d'hydrogène.
34
Gourgon, Cécile. "Fabrication et caractérisation optique de fils et boites quantiques CdTe/CdZnTe." Université Joseph Fourier (Grenoble), 1995. http://www.theses.fr/1995GRE10145.
Full textAbstract:
Un certain nombre de techniques ont ete developpees ces dernieres annees pour fabriquer des nanostructures quantiques, principalement dans le domaine des semiconducteurs iii-v. Nous avons realise des fils et des boites quantiques de semiconducteurs ii-vi, a partir de puits quantiques cdte/cdznte, soit par nanolithographie et gravure de structures 2d, soit directement par epitaxie par jets moleculaires avec une croissance en deux etapes. Les proprietes optiques de ces nanostructures ont ete etudiees en photoluminescence a basse temperature (2k). Dans la premiere approche, les nanostructures ont ete obtenues par lithographie electronique et gravure seche. Nous avons developpe une etape de gravure supplementaire consistant en une oxydation anodique de la couche de surface. Cette etape permet de reduire la taille des fils et des boites et d'eliminer la couche de defauts introduite en surface par la premiere gravure. Les etudes optiques ont prouve l'existence de cette couche de defauts d'une epaisseur de 30 nm environ. Elle contient des centres radiatifs qui localisent les excitons et permet d'augmenter le rendement radiatif des structures de largeur superieure a 150 nm. Pour des tailles inferieures, les recombinaisons sur les defauts non radiatifs de surface font chuter l'intensite de luminescence. Pour s'affranchir des problemes dus a la gravure (fluctuations de largeur, defauts non radiatifs), nous avons developpe une autre approche basee sur une croissance epitaxiale directe. Un puits quantique cdte/cdznte est depose sur la face clivee 110 d'un superreseau contraint. Celui-ci induit une modulation de contrainte dans le plan de la recroissance, et donc un confinement lateral dans le puits 110. La luminescence de ces fils quantiques est decalee vers le rouge par rapport a celle du puits 2d. Ce decalage depend de la densite d'excitation, ce qui est explique par le champ piezoelectrique lateral dans les fils
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Rashid, S. M. Shahriar. "Design and Heterogeneous Integration of Single and Dual Band Pulse Modulated Class E RF Power Amplifiers." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1543505207173487.
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36
Bouchikhi, Benachir. "Propriétés physiques des structures métal/isolant/semiconducteur réalisées sur INP(N) à l'aide d'un oxyde natif plasma." Nancy 1, 1988. http://www.theses.fr/1988NAN10085.
Full textAbstract:
On aborde 3 aspects : la passivation du phosphorure d'indium dans un plasma RF d'oxygène, la caractérisation électrique des structures MIS élaborées à l'aide des mesures (C-V), (G-V) et d'autres mesures de spectrométries de niveaux profonds (DLTS-DDLTS), et l'élaboration du schéma équivalent de la structure MIS
37
Couturier, Laurent. "Conception et contrôle in-situ de l'élaboration de lasers à cavité verticale et à émission surfacique." Grenoble INPG, 1996. http://www.theses.fr/1996INPG0194.
Full textAbstract:
Ce memoire est consacre a la conception et la mise au point du controle in-situ de la croissance de lasers a cavite verticale et a emission surfacique (vcsel). Les structures laser sont elaborees par epitaxie par jets moleculaires a source gazeuse et realisees par l'empilement de couches minces a base de semi-conducteurs gaas/algaas. Leur longueur d'onde d'emission va dependre directement des caracteristiques optiques des couches deposees. Une etude theorique est d'abord menee sur la conception de ces structures. Nous commencons par determiner les constantes optiques des materiaux qui les composent en portant une attention particuliere a l'effet excitonique dans les puits quantiques. L'utilisation du formalisme matriciel nous permet de decrire la propagation des ondes electromagnetiques dans n'importe quelle structure multicouche. Nous pouvons alors simuler le comportement optique de n'importe quel empilement de couches minces, en particulier des miroirs de bragg et des microcavites que constituent ces lasers. Un chapitre est ensuite consacre a l'elaboration des vcsel. Une description precise des contraintes imposees par la machine et de l'optimisation des conditions de croissance est presentee. Cette etude fait apparaitre la necessite de disposer d'un moyen de controle in-situ des couches realisees. Le dernier chapitre presente la mise au point de la methode de controle. La croissance est interrompue apres que le miroir inferieur et la cavite aient ete epitaxies. A partir d'un spectre de reflectivite realise sur cette structure incomplete, un algorithme de type recuit simule nous permet de determiner precisement les flux et par consequent les epaisseurs et les compositions des couches de la premiere partie de la croissance. La correction de la structure est obtenue par une modification des temps d'epitaxie du miroir superieur. L'utilisation de cette technique nous a permis de fixer la longueur d'onde du pic fabry-perot de la structure complete avec une precision de 0,15%
38
Christoforou, Georges. "Conception de préamplificateurs intégrés pour fonctionnement à basse température et sous rayonnement intense." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10031.
Full textAbstract:
Le grand nombre de voies d'acquisition des signaux issus du calorimetre electromagnetique du detecteur atlas (machine lhc) pose un probleme de cablage et des solutions prevoyant le placement de la partie amont de la chaine electronique d'acquisition dans le meme milieu que l'element froid de detection ont ete envisagees. L'electronique amont doit donc etre resistante aux radiations (2 10#1#4n/cm#2, 0. 5mrad), fonctionner a la temperature de l'argon liquide (89k), avoir un faible niveau de bruit, une non-linearite inferieure a 1%, consommer peu et etre rapide (40mhz). Dans le cadre de ce projet nous avons explore les possibilites offertes par les differentes technologies. Nous avons retenu les technologies asga qui resistent aux radiations et fonctionnent jusqu'a des temperatures cryogeniques. Nous avons mis en evidence au moyen de caracterisations (a basse temperature) le fait que les technologies asga sont capables de fonctionner dans un tel environnement. Les amplificateurs concus presentent une amelioration de leurs performances quand ils fonctionnent a basse temperature (reduction du bruit, reduction de la puissance dissipee augmentation du gain) rencontrant les contraintes posees par la calorimetrie dans atlas, faible niveau de bruit, faible puissance dissipee, grande dynamique de sortie et bonne non-linearite integrale, mais ne sont pas encore capables d'assurer un niveau de fiabilite de fabrication suffisant. Nous abordons egalement le probleme de la simulation des mesfet a basse temperature. Les modeles manquant, nous avons employe pour la simulation des parametres spice extraits a la temperature de l'azote liquide. Finalement, nous avons approfondi la simulation du bruit des circuits analogiques et mis en evidence les problemes existant ainsi que les precautions a prendre afin de rendre la simulation spice du bruit plus fiable.
39
Weil, Thierry. "Etude theorique du transport perpendiculaire aux couches dans les semiconducteurs 3-5 modules suivant une dimension." Paris 6, 1987. http://www.theses.fr/1987PA066099.
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Proposition d'un modele pour le transport inelastique et application au transport assiste par phonons entre deux puits quantiques, a la capture des porteurs par le puits quantique d'un laser sch, au transport dans les pseudoalliages quaternaires et dans les superreseaux. Analyse des differents modeles de l'effet tunnel et discussion de la duree de l'effet tunnel; application aux diodes a double barriere et mise en evidence de l'equivalence des descriptions basees sur l'effet tunnel resonnant et sur l'effet tunnel sequentiel, au moins en regime continu; effets des diffusions, developpement d'un modele sequentiel a partir du formalisme d'oppenheimer. Algorithme de calcul du transport perpendiculaire dans les heterostructures (approche de la cao des structures de bande)
40
Peng, Kun. "III-V Compound Semiconductor Nanowire Terahertz Detectors." Phd thesis, 2016. http://hdl.handle.net/1885/117040.
Full textAbstract:
III-V semiconductor nanowires have emerged over the past decade
as promising nano-components for future electronic and
optoelectronic devices and systems, including field-effect
transistors, light-emitting diodes, photodetectors, lasers and
solar cells. Recently, III-V semiconductor nanowires have been
considered as ideal candidates for photoconductive terahertz
(THz) detection, as they possess many desirable properties, such
as a direct and tunable band gap, good carrier mobility and short
carrier lifetime (on the picosecond to nanosecond timescale). Due
to the one-dimensional structure and nanoscale size, such III-V
nanowire THz detectors are promising as building blocks for
advanced THz systems with compact configuration and enhanced
functionalities (i.e. sub-wavelength resolution and high
polarisation sensitivity).
This dissertation presents the first attempt to examine the
suitability of III-V semiconductor nanowires for their
applications as photoconductive THz detectors. At first, a series
of GaAs/AlGaAs core-shell nanowires were grown (using Au-catalyst
metalorganic vapour phase epitaxy technique), characterised and
compared for selection to detect the THz signal in a THz
time-domain spectroscopy (THz-TDS) system. The fabricated
GaAs/AlGaAs single nanowire THz detectors exhibited a pA-level
THz response with good signal-to-noise ratio and high
polarisation sensitivity however a narrow detection bandwidth (in
the range of 0.1-0.6 THz). The origin of the narrow bandwidth for
single nanowire detectors was thoroughly investigated using
finite-difference time-domain (FDTD) simulations, revealing that
the limited bandwidth arose from the strong low frequency
resonance caused by the specific device geometry design (rather
than the nanowire itself). By adjusting and optimising the
nanowire detector geometry, broadband (0.1-1.6 THz) GaAs/AlGaAs
single nanowire THz detectors were demonstrated. Furthermore, due
to the nanoscale active material fabricated on an insulating
substrate (z-cut quartz), single nanowire photoconductive THz
detectors showed a very low dark current and a resultant
low-noise nature when compared with the traditional (bulk)
photoconductive THz detectors. This relaxes the ultra-short
carrier lifetime requirement for the (semiconductor) detection
material for photoconductive THz detection, since in traditional
photoconductive detector the detection material has to have a
carrier lifetime of a few picoseconds to minimise the noise
current. Therefore, nanowires with longer carrier lifetime can
also be used for photoconductive THz detection. Based on above
findings, the high-quality core-only InP nanowires (grown by
selective-area metalorganic vapour phase epitaxy technique) were
investigated for photoconductive THz detection. With previously
optimised device geometry and superior optoelectronic properties
of InP nanowires, InP single nanowire THz detectors were
fabricated and found to exhibit a broadband response (0.1-2.0
THz) and excellent sensitivity, which were then used to measure
the transmission spectra for real material characterisation with
performance comparable to the traditional (bulk) detectors. A
longer time-domain sampling window (compared to the traditional
bulk detectors) and thus a higher spectral response resolution
were obtained for the InP single nanowire THz detectors, which
have been ascribed to the small active material volume and thick
THz-transparent z-cut quartz substrate, enabling the single
nanowire detector to have less Fabry-Pérot reflections in
measured signal. Furthermore, it was found that the contact
quality significantly affects THz detector performance and is
particularly crucial for the performance and reliability of
single nanowire detectors due to their large surface-to-volume
ratio. In the final part of this work, an axial n+-i-n+ InP
nanowire structure was designed and investigated for use in
nanowire THz detectors. The improved contact quality (due to
contact doping) has led to further improvement of the nanowire
THz detector performance particularly in its signal-to-noise
ratio.
In summary, this thesis demonstrates a series of
photoconductive THz detectors fabricated from different III-V
semiconductor nanowire materials and structures, showing
excellent bandwidth and sensitivity, approaching that of the
conventional THz detectors. The nanowire device design,
fabrication, characterisation and related optical simulations
described in this work have provided deep insights into the
characteristics of the single nanowire THz detectors, which may
serve as a useful guidance for future development of nano-device
based THz systems.
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Narangari, Parvathala. "III-V Semiconductor Nanostructures for Photoelectochemical Water Splitting." Phd thesis, 2019. http://hdl.handle.net/1885/160829.
Full textAbstract:
The desire for the development of renewable energy technologies is ever growing to sustain global socio-economic growth and meet future technological developments due to declining fossil fuel reserves and growing environmental concerns of their by-products. Although photovoltaics is well established as a renewable technology to generate clean energy, it is intermittent in nature and hence storing solar energy for short and long-term applications is still challenging. Hydrogen generation via photoelectrochemical (PEC) water splitting is one of the promising routes to secure a sustainable, green, storable and portable form of energy. III-V semiconductors have gained intense research interest for PEC water splitting applications owing to their outstanding properties such as variable band gaps to capture the entire solar spectrum, high absorption coefficients and high crystalline quality. In addition, nanostructures possess several essential attributes towards achieving efficient water splitting such as enhanced light absorption, reduced carrier transfer length and large surface area.
This thesis report on GaN and InP nanopillar (NP) photoelectrodes fabricated using a top-down approach for PEC water splitting. This work involves the fabrication of large area GaN and InP NPs using inductively coupled plasma (ICP) etching of the respective wafers masked by a self-organized random mask technique, followed by a study of their PEC performance. NP photoelectrodes exhibited a remarkable improvement in PEC performance compared to their planar counterparts due to the enhanced absorption and increased semiconductor/electrolyte interface area. The PEC performance of the GaN NP photoanodes was shown to be influenced by doping concentration, NP dimensions such as diameter and length, and band gap engineering of the GaN NPs. The PEC performance of the InP NPs was strongly dependent on the surface damage of NPs, which was eliminated by wet treatment of the NPs in sulfur-oleylamine (S-OA) solution. Finally, long-term photo-stability was demonstrated for both NP photoelectrodes.
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Li, ChyiShiun. "Radiation effects in III-V compound semiconductor heterostructure devices." Thesis, 2002. http://hdl.handle.net/1957/31095.
Full textAbstract:
The radiation effects in III-V heterojunction devices are investigated in this
thesis. Two types of heterojunction devices studied are InGaP/GaAs single heterojunction
bipolar transistors (SHBTs) and GaN-based heterojunction light emitting
diodes (LEDs). InGaP/GaAS HBTs are investigated for high energy (67 and 105
MeV) proton irradiation effects while GaN heterojunction LEDs are studied for
neutron irradiation effects. A compact model and the parameter extraction procedures
for HBTs are developed, and hence the I[subscript C]--V[subscript CE] characteristics of pre- and
post-irradiation HBTs can be simulated by employing the developed model.
HBTs are electrically characterized before and after proton irradiation. Overall,
the studied HBT devices are quite robust against high energy proton irradiation.
The most pronounced radiation effect shown in SHBTs is gain degradation. Displacement
damage in the bulk of base-emitter space-charge region, leading to excess
base current, is the responsible mechanism for the proton-induced gain degradation.
The performance degradation depends on the operating current and is generally less
at higher currents. Compared to the MBE grown devices, the MOVPE grown HBTs
show superior characteristics both in initial performance and in proton irradiation
hardness. The 67 MeV protons cause more damage than 105 MeV protons due to
their higher value of NIEL (non-ionizing energy loss). The HBT I-V characteristics
of pre- and post-irradiated samples can be simulated successfully by employing the
developed model.
GaN heterojunction LEDs are electrically and optically characterized before
and after neutron irradiation. Neutron irradiation causes changes in both the I-V
characteristic and the light output. Atomic displacement is responsible for both
electrical and optical degradation. Both electrical and optical properties degrade
steadily with neutron fluence producing severe degradation after the highest fluence
neutron irradiation. The light output degrades by more than 99% after 1.6x10����� n/cm�� neutron irradiation, and the radiation damage depends on the operating current and is generally less at higher currents.Graduation date: 2003
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HUANG, ZHEN-ZHI, and 黃禎治. "Study on III-V compound semiconductor heterojunction bipolar transistors." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/96710582306070924626.
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"Interdigitated metal-semiconductor-metal (MSM) photodetector on III-V compound semiconductor materials." Chinese University of Hong Kong, 1995. http://library.cuhk.edu.hk/record=b5888464.
Full textAbstract:
by Hiu-suen Choy.Thesis (M.Phil.)--Chinese University of Hong Kong, 1995.
Includes bibliographical references (leaves [124]-131).
Acknowledgements
Abstract
Chapter Chapter 1 --- Introduction --- p.1-1
Chapter Chapter 2 --- Basic Theory for MSM Photodetectors --- p.2-1
Chapter 2.1 --- Schottky-Mott Theory for Ideal metal-Semiconductor Contact --- p.2-1
Chapter 2.2 --- Modifications to Schottky-Mott Theory for Practical Metal Semiconductor Contact --- p.2-4
Chapter 2.3 --- Energy Band of Metal-semiconductor-metal (MSM) Structures --- p.2-6
Chapter 2.4 --- Dark Current Voltage Characteristics for MSM Structure --- p.2-12
Chapter 2.5 --- Capacitance for Interdigitated MSM Photodetectors --- p.2-16
Chapter 2.6 --- Basic mechanism of the MSM Photodetector --- p.2-19
Chapter 2.7 --- DC Responsity and Quantum Efficiency of the Interdigitated MSM Photodetector --- p.2-20
Chapter 2.8 --- Speed Performance of the Interdigitated MSM Photodetector --- p.2-21
Chapter Chapter 3 --- Device Fabrication and Packaging --- p.3-1
Chapter 3.1 --- Metallization Pattern --- p.3-1
Chapter 3.2 --- Device Fabrication --- p.3-7
Chapter 3.3 --- Device Packaging --- p.3-8
Chapter Chapter 4 --- Experimental Description --- p.4-1
Chapter 4.1 --- Experimental Procedures --- p.4-1
Chapter 4.2 --- Equipment Description --- p.4-3
Chapter Chapter 5 --- 1.3μm In0.53Ga0.47As Metal-Semiconductor-Metal Photodetector Grown by Low-Pressure MOCVD Using Tertiarybutylarsine --- p.5-1
Chapter 5.1 --- General Description --- p.5-1
Chapter 5.2 --- Structure of the Photodetector --- p.5-2
Chapter 5.3 --- Experimental Results --- p.5-6
Chapter 5.4 --- Data Analysis and Discussion --- p.5-14
Chapter 5.5 --- Summary --- p.5-24
Chapter Chapter 6 --- The Performance of 0.85μm Semi-Insulated GaAs MSM Photodetector with Different Interdigitated Spacings --- p.6-1
Chapter 6.1 --- General Description --- p.6-1
Chapter 6.2 --- Experimental Results --- p.6-2
Chapter 6.3 --- Data Analysis and Discussion --- p.6-17
Chapter 6.4 --- Summary --- p.6-27
Chapter Chapter 7 --- Optical Control of Polarity in Short Electrical Pulses Generated from Coplanar Waveguide MSM Photodetectors --- p.7-1
Chapter 7.1 --- General Description --- p.7-1
Chapter 7.2 --- "Structure, Fabrication and Experimental Set-up" --- p.7-1
Chapter 7.3 --- Experimental Results --- p.7-4
Chapter 7.4 --- Data Analysis and Discussion --- p.7-11
Chapter 7.5 --- Applications --- p.7-18
Chapter Chapter 8 --- Conclusion --- p.8-1
References
Publications
45
Tsung-HanTsai and 蔡宗翰. "Investigation of III-V Compound Semiconductor Schottky-Type Gas Sensors." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/24484513028779256548.
Full textAbstract:
博士國立成功大學
微電子工程研究所碩博士班
98
In this dissertation, a series of III-V compound semiconductor Schottky-type gas sensors, including Schottky diodes and heterostructure field-effect transistors, are fabricated and studied. III-V compound semiconductors, such as AlGaN- and InAlAs-based materials, are served as sensing platforms. The larger band gaps of those materials make the fabricated devices suitable for high-temperature operation. Pd and Pt are used as sensing metals due to their excellent catalytic activity toward hydrogen and ammonia gases, respectively. The electrical characteristics and gas-sensing performance of these sensors are investigated at different temperatures. Furthermore, the influence of gate insulator on the sensing performance of each sensing device is studied. First, hydrogen-sensing characteristics of metal semiconductor (MS) Pd/AlGaN-based and metal-oxide-semiconductor (MOS) Pd/SiO2/AlGaN-based Schottky diode-type sensors are studied. Thermionic emission (TE) equation is employed to characterize the current-voltage (I-V) behaviors of the studied devices under exposing to hydrogen gas. Schottky barrier height, ideality factor, and series resistance extracted from TE equation, are found to be sensitive to hydrogen gases with different concentrations. Hydrogen sensing behaviors of MS and MOS devices are investigated in terms of those diode parameters, sensing response, and response time. Second, ammonia-sensing characteristics of a Pt/AlGaN-based Schottky diode are studied. Pt metal shows high catalytic activity to ammonia gas. It is, therefore, used as the sensing metal for ammonia detection. Based on the “triple-point theorem”, SiO2 layer is employed to increase the “boundaries” between SiO2, Pt metal, and NH3 molecules, thus facilitating the dissociation of NH3 molecules. The temperature-dependent NH3 sensing behaviors are investigated for the studied device. Third, metamorphic high electron mobility transistors (MHEMTs)-type hydrogen sensors with catalytically active palladium (Pd) gate electrodes are fabricated and studied. Hydrogen-induced effects on electrical parameters of a field-effect transistor (FET), such as threshold voltage, transconductance, and on-off current ratio are investigated. Equilibrium adsorption and kinetic adsorption are studied for the devices. In addition, an MHEMT with thermally-grown gate oxide are also fabricated to be compared with the metal-oxide (MS) Pd/MHEMTs. It is found that the electrical and sensing performance of the MHEMTs is significantly improved by the thermally-grown gate oxide. Based on the good results and compatibility of fabrication process of these devices, the studied devices show the promise for the integration of high-performance sensor and micro-electro-mechanical system (MEMS).
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Liu, Po-Chun, and 劉柏均. "Fundamental Studies and Applications of III-V Compound Semiconductor Wafer Bonding." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/98555331287451114209.
Full textAbstract:
博士國立交通大學
材料科學與工程系所
93
The main topics of this thesis can be divided into two categories: (1) The investigation of boned interfaces of III-V compound semiconductors; (2) Applications of III-V compound semiconductors wafer bonding to optoelectronic devices. In the first category, the effects of annealing temperature on the morphology and the change of electrical property of bonded interfaces were discussed. In addition, the effects of the rotational misalignments and relative surface misorientations between two wafers on electrical resistance of bonded wafers were also studied. In the second category, a seed layer was bonded and transferred to a large lattice mismatched substrate first. Then, the heteroepitaxy layer was grown on the large lattice mismatched substrate successfully by means of the seed layer. Furthermore, to optimum the wafer bonding process of high brightness LEDs (Light emitting diodes), an intermediate layer was used to decrease wafer bonding temperature. Si doped n-type (100) GaAs wafers which have native oxide were used for systematically investigation of the bonded interface and the electrical characteristics. For estimating the electrical characteristics of bonded wafer, single GaAs wafers and two-layer bonded stacks were annealed at the same temperature (400-850℃). Experimental results indicated that GaAs bond via an amorphous oxide layer at 400 °C. When temperatures increased above 400 °C, the oxide bonded area declined and finally disappeared. The electrical resistance of bonded interface decreased with the increase of bonded temperature. However, the resistance increased with temperatures exceeding 850 °C. This result caused by the oxygen in-diffusion into n-GaAs and the effect of inversion. P-type GaAs samples were also pressed against each other and annealed under identical thermal conditions. The electrical resistance of bonded interface decreased with the increase of bonded temperature, even the temperatures exceeds 850 °C. Results evidence that the event of inversion of n-GaAs wafers were occurred. Besides, the relationship between various bonding angle and the change of electrical resistance was also studied. Both anti-phase and in-phase structures were bonded at 700 ℃ for 1 hr. It was observed that a thin amorphous layer (about 5 nm) existed at the anti-phase bonded interface. The amorphous layer in the anti-phase bonding structure caused the higher electrical resistance than that was in-phase bonding structure. Layer transfer technique is one of important applications of wafer bonding to optoelectronic devices. A 50 nm n-In0.5Ga0.5P layer with line patterns was transferred to the n-GaP substrate. This line patterned layer acted as a seed layer for quaternary alloy (AlxGa1-x)0.5In0.5P heteroepitaxy. Almost no defects were observed in the transferred layer and only few changes in the optical property. Moreover, it was discovered that the interface electrical resistance rose while surface misorientations were added. The quaternary alloy which had low defect density and fine optoelectronic property was grown on the line patterned substrate successfully. Wafer-direct-bonding technique is usually used to the fabrication of high brightness LEDs. However, bonding processes were usually performed at elevated temperatures, possibly causing degradation in the quality of the LED structure. In addition to this, misorientation between the two bonded wafers may have caused defects between the wafers. In this study, these two problems were solved by bonding the InGaP/GaAs and GaAs wafers with an indium tin oxide (ITO) polycrystalline film at temperatures below 650 ℃. It was found that the bonding occurred mainly through the In transport from the InGaP to ITO, and that the electrical resistance decreased with the bonding temperature. Then, the intermediate layer was used to fabricate high brightness LEDs. Compared with wafer direct bonding technique, the lower threshold voltage and the higher operating current can be gained by using the ITO intermediate layer.
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WU, ZHONG-ZHENG, and 吳忠政. "The study on III-V compound semiconductor hetero-structure bipolar transistors." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/34552352073463873263.
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Li, Kang. "Growth and characterisation of [delta]-doped III-V compound semiconductors." Phd thesis, 1996. http://hdl.handle.net/1885/138430.
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Crain, Nathaniel Charles. "Redesign and refurbishment of a III-V compound semiconductor wet oxidation furnace." 2004. http://etd.nd.edu/ETD-db/theses/available/etd-04162004-140016/.
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González, Debs Mariam. "Nanoscopic diffusion studies on III-V compound semiconductor structures : experiment and theory /." 2005. http://catalog.hathitrust.org/api/volumes/oclc/70854057.html.
Full text