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Mahajumi, Abu Syed. "InAs/GaSb quantum well structures of Infrared Detector applications. : Quantum well structure." Thesis, IDE, Microelectronics and Photonics, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-3848.
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The detection of MWIR (mid wavelength infrared radiation) is the important for industrial, biomedical and military applications.desirable for the radiation detector to operate in the middle wavelength IR (MWIR) band corresponding to a wavelength band ranging from about 3 microns to about 5 microns.Such MWIR detectors allow forobjects having a similar thermal signature. In addition, MWIR detectors may be used in low power applications such as in night vision for surveillance of personnel.
Now a day commercially available uncooled IR sensors operating in MWIR region (2 – 5 μm) use microbolometric detectors which are inherently slow. The novel detector of InAs/GaSb quantum well structures overcomes this limitation. However, third-generation high-performance IR FPAs are already an attractive proposition to the IR system designer. They covered such as multicolour (at least two, and maybe more different spectral bands) with the possibility of simultaneous detection in both space and time, and ever larger sizes of, say, 2000 × 2000, and operating at higher temperatures, even to room temperature, for all cut-off wavelengths.These hetero structures have a type-II band alignment such that the conduction band of InAs layer is lower than the valence band of GaSb layer. The effective bandgap of thesestructures can be adjusted from 0.4 eV to values below 0.1 eV by varying the thickness of constituent layers leading to an enormous range of detector cutoff wavelengths (3-20 This work is focused on the various key characteristics the optical (responsivity and detectivity) and electrical (surface leakage & dark current) of infrared detector and proof of concept is demonstrated on infrared P-I-N photodiodes based on InAs/GaSb superlattices with ~8.5 μm cutoff wavelength and bandgap energy ~150 meV operating at 78 K where supression of surface leakage currents is observed. In certain military applications, it isthermal imaging of airplanes, artillery tanks and otherμm).
Nice research work at Halmstad University
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Giannopoulos, Mihail. "Tunable bandwidth quantum well infrared photo detector (TB-QWIP)." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Dec%5FGiannopoulos.pdf.
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Thesis (M.S. in Applied Physics)--Naval Postgraduate School, December 2003.Thesis advisor(s): Gamani Karunasiri, James Luscombe. Includes bibliographical references (p. 59-61). Also available online.
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Ganbold, Tamiraa. "Development of quantum well structures for multi band photon detection." Doctoral thesis, Università degli studi di Trieste, 2015. http://hdl.handle.net/10077/11801.
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2013/2014La ricerca qui presentata è incentrata sullo sviluppo di tecnologie innovative per la produzione di rivelatori di posizione di fasci fotonici veloci (pBPM) per applicazioni in luce di sincrotrone (SR) e laser a elettroni liberi (FEL). Nel nostro lavoro abbiamo proposto un rilevatore in-situche ha dimostrato velocità di risposta ed omogeneità sia per scopi di diagnostica che di calibrazione. I dispositivi sono basati su pozzi quantici (QW) dimateriali semiconduttori InGaAs / InAlAs,che offrono diversi vantaggi grazie alla loro gap di banda diretta e a bassa energia, e all’alta mobilità elettronica a temperatura ambiente. I QW metamorfici diIn0.75Ga0.25As/In0.75Al0.25As contenenti un gas di elettroni bidimensionali (2DEG) sono staticresciuti tramite epitassia a faci molecolari (MBE). Tali materiali presentano alcune differenze notevoli rispetto al diamante, che è il materiale utilizzato per i rivelatori commerciali allo stato dell’arte. Innanzitutto, i costi di produzione e di fabbricazione sono molto più bassi. Poi, il coefficiente di assorbimento è molto superiore al diamante su una vasta gamma di energie di raggi X, il che li rende ampiamente complementari in possibili applicazioni. Inoltre, utilizzando semiconduttori composti si possono fabbricare dispositivi con diverse combinazioni di materiali per la barriera ed il QW;ciòha permesso di ridurre la gap di energia fino a 0.6 eV. La disponibilità e la ripetibilità di fabbricazione dei dispositivi è migliore rispetto a quelle del diamante. Quattro configurazioni di dispositivi a QW pixelati sono stati testati con diverse fonti di luce, come radiazione di sincrotrone, tubo a raggi X convenzionali e laser ultra veloce nel vicinoUV. In questa tesi, dopo aver introdotto i dispositivi a QW per utilizzo comepBPM, saranno riportati e discussii risultati più importanti ottenuti. Tali risultati indicano che questi rivelatori rispondono con tempi di 100-ps a impulsi laser ultraveloci, cioè un fattore 6 più velocirispetto a rivelatori a semiconduttori commerciali allo stato dell’arte. La precisione raggiunta nella stima della posizione del fascio fotonico è di 800nm, da confrontare con i 150nm di rivelatori a diamante commerciali. Inoltre, i nostri rivelatori di fotoni a QW lavorano a tensioni molto inferiori rispetto aipBPMs esistenti.Infine, test con raggi X da radiazione di sincrotrone mostrano come questi dispositivi presentano elevate efficienze di raccolta di carica, che possono essere imputabili all'effetto di moltiplicazione di carica del gas di elettroni 2D all'interno del pozzo. Tutti questi vantaggi rispetto ai rivelatori esistenti basati sul diamante, rendono i nostri dispositivi potenzialmente molto attrattivi come alternativa a quelli commerciali.
XXVII Ciclo
1984
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Wang, Yuekun. "In0.53Ga0.47As-In0.52Al0.48As multiple quantum well THz photoconductive switches and In0.53Ga0.47As-AlAs asymmetric spacer layer tunnel (ASPAT) diodes for THz electronics." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/in053ga047asin052al048as-multiple-quantum-well-thz-photoconductive-switches-and-in053ga047asalas-asymmetric-spacer-layer-tunnel-aspat-diodes-for-thz-electronics(5fd73bd5-aef3-476b-be1b-7498da3f9627).html.
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This thesis is concerned with terahertz (THz) technology from both optical and electronic approaches. On the optical front, the investigation of optimised photoconductive switches included the characterisation, fabrication and testing of devices which can generate and detect THz radiation over the frequency range from DC to ~ 2.5 THz. These devices incorporated semiconductor photoconductors grown under low temperature (LT) Molecular Beam Epitaxy (MBE) conditions and using distributed Bragg reflectors (DBRs). The material properties were studied via numerous characterisation techniques which included Hall Effect and mid infrared reflections. Antenna structures were fabricated on the surface of the active layers and pulsed/continuous wave (CW) signal absorbed by these structures (under bias) generates photocurrent. With the help of the DBRs at certain wavelengths (800 nm and 1550 nm), the absorption coefficient at the corresponding illumination wavelength increased thus leading to significant increase of the THz output power while the materials kept the desirable photoconductive material properties such as high dark resistivity and high electron mobility. The inclusion of DBRs resulted in more than doubling of the THz peak signals across the entire operating frequency range and significant improvements in the relative THz power. For the THz electronic approach, a new type of InP-based Asymmetric Spacer Tunnel Diode (ASPAT), which can be used for high frequency detector, was studied. The asymmetric DC characteristics for this novel tunnel diode showed direct compatibility with high frequency zero-bias detector applications. The devices also showed an extreme thermal stability (less than 7.8% current change from 77 K to 400 K) as the main carrier transport mechanism of the ASPAT was tunnelling. Physical models for this ASPAT diode were developed for both DC (direct current) and AC (alternating current) simulations using the TCAD software tool SILVACO. The simulated DC results showed almost perfect matches with measurements across the entire temperature range from 77 K to 400 K. From RF (radio frequency) measurements, the intrinsic diode parameters were extracted and compared with measured data. The simulated zero biased detector circuits operating at 100 GHz and 240 GHz using the new InGaAs-AlAs ASPAT diode (4*4 micrometer square) showed comparable voltage sensitivities to state of the art Schottky barrier diodes (SBDs) detectors but with the added advantage of excellent thermal stability.
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Psarakis, Eftychios V. "Simulation of performance of quantum well infrared photocetectors." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Jun%5FPsarakis.pdf.
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Thesis (M.S. in Applied Physics and M.S. in Electrical Engineering)--Naval Postgraduate School, June 2005.Thesis Advisor(s): Gamani Karunasiri, James Luscombe, Robert Hutchins, John Powers. Includes bibliographical references (p. 129-131). Also available online.
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Hanson, Nathan A. "Characterization and analysis of a multicolor quantum well infrared photodetector." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Jun%5FHanson.pdf.
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Thesis (M.S. in Applied Physics)--Naval Postgraduate School, June 2006.Thesis Advisor(s): Gamani Karunasiri, James H. Luscombe. "June 2006." Includes bibliographical references (p. 49-50). Also available in print.
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Lantz, Kevin R. "Two color photodetector using an asymmetric quantum well structure." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Jun%5FLantz.pdf.
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Xu, Yuanjian Yariv Amnon. "Quantum well intersubband transition detection and modulation /." Diss., Pasadena, Calif. : California Institute of Technology, 1997. http://resolver.caltech.edu/CaltechETD:etd-05112005-153655.
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Yeo, Hwee Tiong. "High responsivity tunable step quantum well infrared photodetector." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Dec%5FYeo.pdf.
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Konukbay, Atakan. "Design of a voltage tunable broadband quantum well infrared photodetector." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Jun%5FKonukbay.pdf.
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Hickey, Thomas R. "Temperature dependence of dark current in quantum well infrared detectors." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Jun%5FHickey.pdf.
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Jiang, Lin. "Investigation of a novel multicolor quantum well infrared photodetector and advanced quantum dot infrared photodetectors." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0001249.
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Sim, Koon-hung Steven, and 沈觀洪. "Antimonide based quantum-well and its application in infrared photodetector." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31223345.
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Memis, Sema. "Ensemble Monte Carlo Modeling Of Quantum Well Infrared Photodetectors." Phd thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/2/12607291/index.pdf.
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Quantum well infrared photodetectors (QWIPs) have recently emerged as a potential alternative to the conventional detectors utilizing low bandgap semiconductors for infrared applications. There has been a considerable amount of experimental and theoretical work towards a better understanding of QWIP operation, whereas there is a lack of knowledge on the underlying physics. This work provides a better understanding of QWIP operation and underlying physics through particle simulations using the ensemble Monte Carlo method. The simulator incorporates Gamma, L, and X valleys of conduction band as well as the size quantization in the quantum wells. In the course of this work, the dependence of QWIP performance on different device parameters is investigated for the optimization of the QWIP structure.
The simulations on AlGaAs/GaAs QWIPs with the typical Al mole fraction of 0.3 have shown that the L valley of the conduction band plays an important role in the electron capture. A detailed investigation of the important scattering mechanisms indicates that the capture of the electrons through the L valley quantum well (L-QW) affects the device performance significantly when Gamma and L valley separation is small. The characteristics of electron capture have been further investigated by repeating the simulations on QWIPs for quantum well widths of 36 and 44 Å. The results suggest that the gain in the shorter well width device is considerably higher, which is attributed to the much longer lifetime of the photoexcited electrons as a result of lower capture probability (pc) in the device. The effects of the L-QW height on the QWIP characteristics have also been studied by artificially increasing this height from 63 to 95 meV in Al0.3Ga0.7As/GaAs QWIPs. The increase in the L valley (L-QW) height resulted in higher pc and lower gain due to high rate of capturing of these electrons when Gamma and L valley separation is small.
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Corbin, Elizabeth Ann. "Infra-red optical properties of SiGe/Si heterostructures." Thesis, University of Newcastle Upon Tyne, 1995. http://hdl.handle.net/10443/810.
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We present full-scale relativistic pseudopotential calculations of the first-order susceptibility in p-type SiGe/Si multiple quantum well structures with a view to exploring the suitability of such systems for infrared applications in the 3-5yrn and 8-15itm ranges. A derivation of an expression for the linear susceptibility, or absorption, is given and the frequency dependence of the linear response due to transitions between the valence minibands is determined. The microscopic origin of the absorption is demonstrated for both parallel and normal incident light. Comparisons between calculated and experimental results are presented and shown to be in good agreement. The effects of changing well width, temperature, doping concentration and germanium concentration in the well are considered. We also consider Auger recombination and discuss the possibility of engineering the miniband structure in order to prevent certain Auger processes occuring, Preliminary results from full scale Auger calculations are also presented.
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Touse, Michael P. "Demonstration of a near and mid-infrared detector using multiple step quantum wells." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03sep%5FTouse.pdf.
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Hoang, Vu D. "Charge transport study of InGaAs QWIPs /." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Jun%5FHoang.pdf.
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Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, June 2004.Thesis advisor(s): Nancy M. Haegel, John Powers. Includes bibliographical references (p. 53-54). Also available online.
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Kaldirim, Melih. "Dual And Single Color Mid-wavelength Infrared Quantum Well Photodetectors." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/2/12609900/index.pdf.
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Quantum Well Infrared Photodetector (QWIP) technology is promising for the development of large format low cost single and dual/multi color infrared sensor arrays. Thanks to the mature III-V semiconductor technology, QWIP focal plane arrays (FPAs) provide high uniformity and excellent noise equivalent temperature difference (NETD) in both long wavelength infrared (LWIR 8-12 
m) and mid wavelength infrared (MWIR 3-5 &
#61549
m) bands. This thesis work focuses on the development of large format single and dual color MWIR QWIP FPAs. For single band MWIR detection, we report QWIP FPAs on InP substrate as an alternative to the GaAs based MWIR QWIPs suffering from the degrading effects of lattice mismatched epitaxy. In the course of this work, epitaxial growth conditions of the device structure were optimized and 640×
512 AlInAs/InGaAs QWIP FPAs on InP substrate have been fabricated yielding NETD of 22 mK (f/1.5) and background limited performance (BLIP) temperature as high as 115 K In the second part, we report the first voltage tunable 640×
512 dual color MWIR QWIP FPA. After optimizing epitaxial growth of AlGaAs/InGaAs material system, we have designed and implemented the device structure to yield voltage tunable spectral response in two different windows in the MWIR band. The FPA provides NETDs of 60 and 30 mK (f/1.5) in colors 1 and 2. The results are very encouraging for the development of low cost dual/multi color FPAs since our approach utilizes one In bump per pixel allowing fabrication of dual color FPAs with the same process steps for single color FPAs.
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Tomlinson, Andrew Michael. "Terahertz detection and electric field domains in multiple quantum wells." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302363.
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Chaisakul, Papichaya. "Ge/SiGe quantum well devices for light modulation, detection, and emission." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00764154.
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This PhD thesis is devoted to study electro-optic properties of Gemanium/Silicon-Germanium (Ge/SiGe) multiple quantum wells (MQWs) for light modulation, detection, and emission on Si platform. It reports the first development of high speed, low energy Ge/SiGe electro-absorption modulator in a waveguide configuration based on the quantum-confined Stark effect (QCSE), demonstrates the first Ge/SiGe photodiode with high speed performance compatible with 40 Gb/s data transmission, and realizes the first Ge/SiGe light emitting diode based on Ge direct gap transition at room temperature. Extensive DC and RF measurements were performed on each tested prototype, which was realized using the same epitaxial growth and fabrication process. Simple theoretical models were employed to describe experimental properties of the Ge/SiGe MQWs. The studies show that Ge/SiGe MQWs could potentially be employed as a new photonics platform for the development of a high speed optical link fully compatible with silicon technology.
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Karkhanehchi, Mohammad Mehdi. "Generation and detection of short optical pulses using semiconductor devices." Thesis, University of Glasgow, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360165.
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Wong, Alan Lip Yau. "Study of Inâ‚â†-â†xâ†-â†yGaâ†xAlâ†yAs multiple quantum well infrared photodetectors grown on GaAs substrates." Thesis, University of Hull, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273817.
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Bigioli, Azzurra. "Performance evaluation of a quantum-well infrared photodetector in patch-antenna architecture." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13438/.
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Nel presente lavoro di tesi si dimostra il miglioramento delle perfomances di un detector basato su pozzi quantici (QWIP-Quantum Well Infrared Photo detector)(n-type GaAs/AlGaAs) nel range infrarosso (λ ≈8.6µm), processato in un array di nano-antenne a doppio metallo. I Quantum Well detectors generano fotocorrente attivando transizioni intersottobanda nel supereticolo di pozzi quantici. Le prestazioni di questi detectors sono deteriorate dal rumore associato alla corrente di dark, proporzionale all’area del detector e dipendente esponenzialemente dalla temperatura. In questo lavoro, si dimostra che le antenne
patches agiscono da micro-cavitá che confinano il campo elettrico
incidente in uno strato di semiconduttore con dimensioni minori della lunghezza d’onda, evitano la regola di selezione intersottobanda e raccolgono fotoni da un’area maggiore delle dimensioni fisiche del dispositivo
stesso, riducendo la corrente di dark senza diminuire la fotocorrente. Il miglioramento delle prestazioni del detector é espresso in termini di area di collezione Acoll e di
focusing factor, l’aumento di campo locale. Queste quantitá sono state estratte
da spettri di riflettivitá presi tramite spettroscopia infrarosso a Trasformata di Fourier
(FTIR) a 300K. Caratteristiche tensione-corrente sono state misurate in condizioni dark e di background (300K) da 4K a 300K, e paragonate ad un dispositivo con la stessa regione attiva ma processato con una faccetta a 45 °. Da queste curve la temperatura di BLIP (Background Infrared Limited Performance) è stata ricavata. Misure di fotocorrente in funzione del bias sono state
prese tramite tecnica con amplificatore lock-in. Le figure di merito responsivitá e detectivity sono state estratte dalle misure di fotocorrente, dopo la calibrazione della potenza
radiativa incidente. Queste misure mostrano un miglioramento di
10K nelle performaneces rispetto al dispositivo
mesa, dimostrando un’elevata
sensibilitá fino a temperatura ambiente.
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Davies, Graeme John. "Optically detected X-ray absorption spectroscopy (OD-XAS) study of InGaN/GaN quantum well and quantum dot nanostructures." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516410.
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InGaN/GaN single quantum well (SQW) and quantum dot (QD) samples were studied using optically detected X-ray absorption spectroscopy (OD-XAS). This is a powerful technique, capable of linking local structural environment information with the luminescence emission processes present. Ga K-edge OD-EXAFS analysis shows this technique to be site-selective for these samples and, from the emission related to the QW or QD structure, a percentage indium value was determined for each sample. Possible reasons why this siteselectivity is observed are considered, along with the implication of the results with respect to the nature of the mechanism responsible for exciton localisation within these structures. Further investigations were performed on the QD sample, including a depth profiling study based on spectra obtained at several different excitation energies and an analysis of the OD-XANES at the N K-edge. The application of pumpprobe micro-imaging OD-XAS to these types of samples is also examined.
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Grave, Ilan Yariv Amnon Yariv Amnon. "GaAs quantum well devices for detection and nonlinear optics in the mid-infrared /." Diss., Pasadena, Calif. : California Institute of Technology, 1993. http://resolver.caltech.edu/CaltechETD:etd-08272007-111424.
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Alves, Fábio Durante Pereira. "Three-band quantum well infrared photodetector using interband and intersubband transitions." Instituto Tecnológico de Aeronáutica, 2008. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=523.
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This thesis presents the modeling, design, fabrication and characterization of a quantum well infrared photodetector (QWIP) capable of detecting near infrared (NIR), mid wavelength infrared (MWIR) and long wavelength infrared (LWIR), simultaneously. The NIR detection was achieved using interband transition while MWIR and LWIR were based on intersubband transition in the conduction band. The quantum-well structure was modeled by solving self-consistently the Schrödinger and Poisson equations with the help of the shooting method. A sample with three different stacks of quantum wells formed by different configurations of GaAs, AlGaAs and InGaAs, separated by n-doped GaAs contact layers was grown on a semi-insulated GaAs substrate using MBE (Molecular Beam Epitaxy). Intersubband absorption in the sample was measured for the MWIR and LWIR using Fourier transform spectroscopy (FTIR) and the measured peak positions were found at 5.3 and 8.7 ?m, respectively which are within 5% of the theoretical values, indicating the good accuracy of the self-consistent model. The test photodetectors were fabricated using a standard photolithography process with exposed middle contacts to allow separate bias and readout of signals from the three wavelength bands. A 45 degree facet was polished to allow light coupling. Performance analyses were conducted in order to obtain the I-V characteristics, responsivity and detectivity of each detection band. The background-limited infrared performance (BLIP) for the LWIR quantum wells shows an upper operating temperature of about 70 K, limiting the overall device. Photocurrent spectroscopy was performed and gave three peaks at 0.84, 5.0 and 8.5 m wavelengths with approximately 0.5, 0.03 and 0.13 A/W peak responsivities for NIR, MWIR and LWIR bands, respectively. Estimated peak detectivities, limited by the number of quantum well repetitions, are 140, 1.6 and 1.2x109 cm.Hz1/2/W for NIR, MWIR and LWIR, respectively. The overall results demonstrate the possibility of detection of widely separated wavelength bands, in a single pixel device, using interband and intersubband transitions in quantum wells.
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Gerbracht, Michael [Verfasser]. "Optically detected resonances induced by far infrared radiation in quantum wells and quantum dots / Michael Gerbracht." München : GRIN Verlag, 2008. http://d-nb.info/997515562/34.
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Kaushik, Sumanth. "Design and application of a soft X-ray detector using GaAs multiple quantum wells." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/37719.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.Includes bibliographical references (leaves 156-163).
by Sumanth Kaushik.
Ph.D.
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Aslan, Bulent. "Physics And Technology Of The Infrared Detection Systems Based On Heterojunctions." Phd thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12604801/index.pdf.
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The physics and technology of the heterojunction infrared photodetectors having different material systems have been studied extensively. Devices used in this study have been characterized by using mainly optical methods, and electrical measurements have been used as an auxiliary method. The theory of internal photoemission in semiconductor heterojunctions has been investigated and the existing model has been extended by incorporating the effects of the difference in the effective masses in the active region and the substrate, nonspherical-nonparabolic bands, and the energy loss per collisions. The barrier heights (correspondingly the cut-off wavelengths) of SiGe/Si samples have been found from their internal photoemission spectrums by using the complete model which has the wavelength and doping concentration dependent free carrier absorption parameters. A qualitative model describing the mechanisms of photocurrent generation in SiGe/Si HIP devices has been presented. It has been shown that the performance of our devices depends significantly on the applied bias and the operating temperature. Properties of internal photoemission in a PtSi/Si Schottky type infrared detector have also been studied. InGaAs/InP quantum well photodetectors that covers both near and mid-infrared spectral regions by means of interband and intersubband transitions have been studied. To understand the high responsivity values observed at high biases, the gain and avalanche multiplication processes have been investigated. Finally, the results of a detailed characterization study on a systematic set of InAs/GaAs self-assembled quantum dot infrared photodetectors have been presented. A simple physical picture has also been discussed to account for the main observed features.
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Hoang, Vu Dinh. "Charge transport study of InGaAs two-color QWIPs." Thesis, Monterey California. Naval Postgraduate School, 2004. http://hdl.handle.net/10945/1574.
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Approved for public release, distribution is unlimitedIn this thesis, a series of experiments were performed to characterize the material properties of InGaAs/GaAs for use in a two-color quantum-well IR photodetector (QWIP) design. Results from room temperature studies using cathodoluminescence and photoluminescence indicated light emission at 858 nm and 1019 nm from GaAs and InGaAs, respectively. Using a direct transport imaging technique, an edge dislocation pattern was observed and shown to be confined to the InGaAs layer of the material. A dislocation density measurement was performed and was shown to be less than 2000 lines/cm. Quantitative intensity level measurements indicated fluctuation in the region of dislocations to be less than 30% of the signal to background level. Finally, a spot mode study using the direct transport imaging method was performed to evaluate the feasibility of using this technique for contact-less diffusion length measurements.
Civilian, Department of Air Force
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Flinn, Gregory Patrick. "Laser spectroscopy of semiconductor quantum wells : optical pumping and optically detected nuclear magnetic resonance." Thesis, University of Southampton, 1991. https://eprints.soton.ac.uk/399448/.
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This thesis describes the experimental results of optical pumping studies made in some Type 1 GaAs/Al0.3Ga0.7As single quantum wells (QWs), ranging in widths from 50 to 200A. Optical pumping uses circularly polarised light to photocreate spin orientated carriers in the QWs. The polarised carriers, principally the electrons, transfer angular momentum to the nuclear spins of the lattice through the Fermi contact hyperfine interaction. The orientated nuclei act back on the electrons through the same interaction. Studies of the nuclear and carrier spin systems may be effected by monitoring the circular polarisation of the recombination luminescence. The Hanle Effect of the electron orientation within the QWs is measured as a function of well width, and of the non-photoexcited hole concentration. Correlation of this data with carrier recombination time measurements produces the magnitude of the carrier Landé factor. Allowing the nuclear field to influence the Hanle curves determines the sign of these g - factors, whence the free conduction electron value is observed to change sign at 55A and become positive for thinner wells. This result is compared to the bulk g -values of GaAs (-0.44) and Al0.3Ga0.7As (+0.40), and modelled using k . p theory to estimate the contributions to g* from the well and barrier materials. Nuclear orientation within the wells is observed by the optical detection of nuclear magnetic resonance (ODNMR), via the application of a radio frequency field (RF) to the orientated nuclear spins. ODNMR of ~ 1011 nuclear spins is measured in almost all the single QWs. The signals are studied as a function of various experimental influences, such as well width, p-type carrier concentration, RF magnitude, optical pumping time, and RF sweep rate. Observation is made of extrinsic lattice strain and spin diffusion of the nuclear magnetization, and results suggest increased nuclear relaxation rates within the barrier. n-type wells show no ODNMR, indicating that incomplete hole relaxation is present within the wells. The very wide and undisplaced Hanle curves observed in this type of well support this view. Nuclear orientation is not observed in some GaAs/InxGa1-xAs QW systems. This null result is discussed in terms of the experimental factors important for its successful observation in the GaAs/Al0.3Ga0.7As systems.
32
Palaferri, Danièle. "Antenna resonators for quantum infrared detectors and fast heterodyne receivers." Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCC083/document.
Full textAbstract:
Ce travail de thèse porte sur la conception et la réalisation de méta-structures pour l’amelioration des performances de détecteurs dans les gammes spectrales du moyen infrarouge et du térahertz (THz). Ces méta-structures sont des matrices de résonateurs métalliques qui actent aussi comme antennes, permettant une meilleure collection des photons et un plus fort confinement du champ électrique. Dans ce manuscrit, j’examine les résultats expérimentaux concernant deux photo-detecteurs infrarouges à puits quantiques (QWIP) résonants à une longueur d'onde de 55.5 µm (5.4 THz) et de 8.6 µm, implémentés dans des réseaux d’antennes patch. La responsivité, la détectivité et les performances thermiques des dispositifs en microcavité sont systématiquement comparées au même détecteur fabriqué en géométrie standard ‘mesa’, pour lequel le rayonnement infrarouge est couplé par le substrat. La cohérence du modèle est évaluée en comparant le gain photoconducteur de chaque structure QWIP. Dans le moyen infrarouge, le fonctionnement à température ambiante avec une source de radiation thermique est démontré pour la première fois. De plus, en exploitant la courte durée de vie des porteurs dans la zone de QWIP, une détection hétérodyne à température ambiante a été démontrée jusqu’aux fréquences de quelques GHz, limitée uniquement par la fréquence de coupure du circuit externe. Dans la dernière partie de ce manuscrit, plusieurs perspectives sont discutées concernant des structures de détecteurs quantiques couplés à la géométrie de résonateurs patch et des architectures inspirées des métamateriaux, avec la perspective d’améliorer davantage les performances des photodétécteursThe present thesis manuscript is about the conception and the realisation of metastructures for the improvement of detector performances in the mid-infrared and terahertz (THz) spectral ranges. These meta-structures are arrays of metal resonators that also act as antennas, allowing a better collection of photons and a stronger confinement of the electric field. In this manuscript, I examine the experimental results regarding a 55.5 µm (5.4 THz) and a 8.6 µm quantum well infrared photodetectors (QWIP), implemented into patch-antennae arrays. The responsivity, the specific detectivity and the thermal performances of the antenna-coupled devices are systematically compared to the same detector processed in standard substrate-coupled ‘mesa’ geometry. In the mid-infrared, the room temperature operation using a thermal radiation source is reported for the first time. Moreover, exploiting the short carrier lifetime in semiconductor quantum wells, a room temperature heterodyne detection is demonstrated, at frequencies up to few GHz, limited only by the cut-off frequency of the external circuit. In the last part of this work, several perspectives are discussed, regarding alternative quantum detector structures coupled to the patch resonators geometry and innovative circuit-like plasmonic architectures, envisioning orders of magnitude improvement in photodetector performances
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Ariyawansa, Gamini. "Semiconductor Quantum Structures for Ultraviolet-to-Infrared Multi-Band Radiation Detection." Digital Archive @ GSU, 2007. http://digitalarchive.gsu.edu/phy_astr_diss/17.
Full textAbstract:
In this work, multi-band (multi-color) detector structures considering different semiconductor device concepts and architectures are presented. Results on detectors operating in ultraviolet-to-infrared regions (UV-to-IR) are discussed. Multi-band detectors are based on quantum dot (QD) structures; which include quantum-dots-in-a-well (DWELL), tunneling quantum dot infrared photodetectors (T-QDIPs), and bi-layer quantum dot infrared photodetectors (Bi-QDIPs); and homo-/heterojunction interfacial workfunction internal photoemission (HIWIP/HEIWIP) structures. QD-based detectors show multi-color characteristics in mid- and far-infrared (MIR/FIR) regions, where as HIWIP/HEIWIP detectors show responses in UV or near-infrared (NIR) regions, and MIR-to-FIR regions. In DWELL structures, InAs QDs are placed in an InGaAs/GaAs quantum well (QW) to introduce photon induced electronic transitions from energy states in the QD to that in QW, leading to multi-color response peaks. One of the DWELL detectors shows response peaks at ∼ 6.25, ∼ 10.5 and ∼ 23.3 µm. In T-QDIP structures, photoexcited carriers are selectively collected from InGaAs QDs through resonant tunneling, while the dark current is blocked using AlGaAs/InGaAsAlGaAs/ blocking barriers placed in the structure. A two-color T-QDIP with photoresponse peaks at 6 and 17 µm operating at room temperature and a 6 THz detector operating at 150 K are presented. Bi-QDIPs consist of two layers of InAs QDs with different QD sizes. The detector exhibits three distinct peaks at 5.6, 8.0, and 23.0 µm. A typical HIWIP/HEIWIP detector structure consists of a single (or series of) doped emitter(s) and undoped barrier(s), which are placed between two highly doped contact layers. The dual-band response arises from interband transitions of carriers in the undoped barrier and intraband transitions in the doped emitter. Two HIWIP detectors, p-GaAs/GaAs and p-Si/Si, showing interband responses with wavelength thresholds at 0.82 and 1.05 µm, and intraband responses with zero response thresholds at 70 and 32 µm, respectively, are presented. HEIWIP detectors based on n-GaN/AlGaN show an interband response in the UV region and intraband response in the 2-14 µm region. A GaN/AlGaN detector structure consisting of three electrical contacts for separate UV and IR active regions is proposed for simultaneous measurements of the two components of the photocurrent generated by UV and IR radiation.
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Ozer, Selcuk. "Insb And Inassb Infrared Photodiodes On Alternative Substrates And Inp/ingaas Quantum Well Infrared Photodetectors: Pixel And Focal Plane Array Performance." Phd thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/3/12606097/index.pdf.
Full textAbstract:
InAsxSb1-x (Indium Arsenide Antimonide) is an important low bandgap
semiconductor whose high quality growth on GaAs or Si substrates is
indispensible for low cost, large format infrared focal plane arrays (FPAs).
Quantum well infrared photodetector (QWIP) technology, relying on mature
semiconductors, is also promising for the above purpose. While AlGaAs/GaAs
has been the standard material system for QWIPs, the search for alternative
materials is needed for better performance. This thesis reports a detailed
investigation of molecular beam epitaxy grown mid-wavelength infrared
InAsxSb1-x photodiodes on alternative substrates, and long wavelength infrared
InP/InGaAs QWIPs.
In the first part of the study, InSb and InAs0.8Sb0.2 photodiodes grown on Si and
GaAs substrates are investigated to reveal the performance degrading
mechanisms due to large lattice mismatch. InAs0.8Sb0.2/GaAs photodiodes yield
peak detectivities of 1.4×1010 and 7.5×
108 cmHz½
/W at 77 K and 240 K, respectively, showing that the alloy is promising for both cooled and near room temperature detectors. Under moderate reverse bias, 80 K RoA product limiting mechanism is trap assisted tunneling, which introduces considerable 1/f noise. InSb/Si photodiodes display peak 77 K detectivity as high as ~1×
1010 cmHz 1/2/W and reasonably high peak quantum efficiency in spite of large lattice mismatch. RoA product of detectors at 80 K is limited by Ohmic leakage with small activation energy (25 meV). Bias and temperature dependence of 1/f noise is in reasonable agreement with Kleinpenning&rsquo
s mobility fluctuation model, confirming the validity of this approach. The second part of the study concentrates on InP/In0.53Ga0.47As QWIPs, and 640×
512 FPA, which to our knowledge, is the largest format InP/InGaAs QWIP FPA reported. InP/InGaAs QWIPs yield quantum efficiency-gain product as high as 0.46 under moderate bias. At 70 K, detector performance is background limited with f/2 aperture up to ~3 V bias where peak responsivity (2.9 A/W) is thirty times higher than that of the Al0.275Ga0.725As/GaAs QWIP with similar spectral response. Impact ionization in InP/InGaAs QWIPs does not start until the average electric-field reaches 25 kV/cm, maintaining high detectivity under moderate bias. The 640×
512 InP/InGaAs QWIP FPA yields noise equivalent temperature difference of ~40 mK at an FPA temperature as high as 77 K and reasonably low NETD even with short integration times (t). 70 K NETD values of the FPA with f/1.5 optics are 36 and 64 mK under &ndash
0.5 V (t=11 ms) and &ndash
2 V (t=650 Rs) bias, respectively. The results clearly show the potential of InP/InGaAs QWIPs for thermal imaging applications requiring short integration times. Keywords: Cooled infrared detectors, InAsSb, QWIP, focal plane array.
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Thomas, Mikkel Andrey. "Integrated optical interferometric sensors on silicon and silicon cmos." Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26674.
Full textAbstract:
The main objective of this research is to fabricate and characterize an optically integrated interferometric sensor on standard silicon and silicon CMOS circuitry. An optical sensor system of this nature would provide the high sensitivity and immunity to electromagnetic interference found in interferometric based sensors in a lightweight, compact package capable of being deployed in a multitude of situations inappropriate for standard sensor configurations. There are several challenges involved in implementing this system. These include the development of a suitable optical emitter for the sensor system, the interface between the various optically embedded components, and the compatibility of the Si CMOS with heterogeneous integration techniques. The research reported outlines a process for integrating an integrated sensor on Si CMOS circuitry using CMOS compatible materials, integration techniques, and emitter components.
36
Ullah, Saeed. "Optical control and detection of spin coherence in multilayer systems." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-10052017-163058/.
Full textAbstract:
Since a decade, spintronics and related physics have attracted considerable attention due to the massive research conducted in these areas. The main reason for growing interest in these fields is the expectation to use the electrons spin instead of or in addition to the charge for the applications in spin-based electronics, quantum information, and quantum computation. A prime concern for these spins to be possible candidates for carrying information is the ability to coherently control them on the time scales much faster than the decoherence times. This thesis reports on the spin dynamics in two-dimensional electron gases hosted in artificially grown III-V semiconductor quantum wells. Here we present a series of experiments utilizing the techniques to optically control the spin polarization triggered by either optical or electrical methods i.e. well known pump-probe technique and current-induced spin polarization. We investigated the spin coherence in high mobility dense two-dimensional electron gas confined in GaAs/AlGaAs double and triple quantum wells, and, it\'s dephasing on the experimental parameters like applied magnetic field, optical power, pump-probe delay and excitation wavelength. We have also studied the large spin relaxation anisotropy and the influence of sample temperature on the long-lived spin coherence in triple quantum well structure. The anisotropy was studied as a function sample temperature, pump-probe delay time, and excitation power, where, the coherent spin dynamics was measured in a broad range of temperature from 5 K up to 250 K using time-resolved Kerr rotation and resonant spin amplification. Additionally, the influence of Al concentration on the spin dynamics of AlGaAs/AlAs QWs was studied. Where, the composition engineering in the studied structures allows tuning of the spin dephasing time and electron g-factor. Finally, we studied the macroscopic transverse drift of long current-induced spin coherence using non-local Kerr rotation measurements, based on the optical resonant amplification of the electrically-induced polarization. Significant spatial variation of the electron g-factor and the coherence times in the nanosecond scale transported away half-millimeter distances in a direction transverse to the applied electric field was observed.Há uma década, a spintrônica e outras áreas relacionadas vêm atraindo considerável atenção, devido a enorme quantidade de pesquisa conduzidas por elas. A principal razão para o crescente interesse neste campo é a expectativa da aplicação do controle do spin do elétron no lugar ou em adição à carga, em dispositivos eletrônicos e informação e computação quânticas. A possibilidade destes spins carregarem informação depende, primeiramente, da habilidade de controlá-los coerentemente, em uma escala de tempo muito mais rápida do que o tempo de decoerência. Esta tese trata da dinâmica de spins em gases de elétrons bidimensionais, em poços quânticos de semicondutores III-V, crescidos artificialmente. Nós apresentamos uma série de experimentos, utilizando técnicas para o controle ótico da polarização de spin, desencadeadas por métodos óticos ou eletrônicos, ou seja, técnicas conhecidas de bombeio e prova e polarização de spin induzida por corrente. Nós investigamos a coerência de spin em gases bidimensionais, confinados em poços quânticos duplos e triplos de GaAs/AlGaAs e a dependência da defasagem com parâmetros experimentais, como campo magnético externo, potência ótica, tempo entre os pulsos de bombeio e prova e comprimento de onda da excitação. Também estudamos a grande anisotropia de relaxação de spin como função da temperatura da amostra, potência de excitação e defasagem entre bombeio e prova, medidos para uma vasta gama de temperatura, entre 5K e 250K, usando Rotação de Kerr com Resolução Temporal (TRKR) e Amplificação Ressonante de Spin (RSA). Além disso estudamos a influência da concentração de Al na dinâmica dos poços de AlGaAs/AlAs, para o qual a engenharia da composição da estrutura permite sintonizar o tempo de defasagem de spin e o fator $ g $ do elétron. Por fim, estudamos a deriva transversal macroscópica da longa coerência de spin induzida por corrente, através de medidas de Rotação de Kerr não-locais, baseadas na amplificação ressonante ótica da polarização eletricamente induzida. Observamos uma variação espacial significante do fator $ g $ e do tempo de vida da coerência, na escala de nanosegundos, deslocada distâncias de meio milímetro na direção transversa ao campo magnético aplicado.
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Venter, Johan H. "Dynamic range and sensitivity improvement of infrared detectors using BiCMOS technology." Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/25267.
Full textAbstract:
The field of infrared (IR) detector technology has shown vast improvements in terms of speed and performance over the years. Specifically the dynamic range (DR) and sensitivity of detectors showed significant improvements. The most commonly used technique of implementing these IR detectors is the use of charge-coupled devices (CCD). Recent developments show that the newly investigated bipolar complementary metal-oxide semiconductor (BiCMOS) devices in the field of detector technology are capable of producing similar quality detectors at a fraction of the cost. Prototyping is usually performed on low-cost silicon wafers. The band gap energy of silicon is 1.17 eV, which is too large for an electron to be released when radiation is received in the IR band. This means that silicon is not a viable material for detection in the IR band. Germanium exhibits a band gap energy of 0.66 eV, which makes it a better material for IR detection. This research is aimed at improving DR and sensitivity in IR detectors. CCD technology has shown that it exhibits good DR and sensitivity in the IR band. CMOS technology exhibits a reduction in prototyping cost which, together with electronic design automation software, makes this an avenue for IR detector prototyping. The focus of this research is firstly on understanding the theory behind the functionality and performance of IR detectors. Secondly, associated with this, is determining whether the performance of IR detectors can be improved by using silicon germanium (SiGe) BiCMOS technology instead of the CCD technology most commonly used. The Simulation Program with Integrated Circuit Emphasis (SPICE) was used to realise the IR detector in software. Four detectors were designed and prototyped using the 0.35 µm SiGe BiCMOS technology from ams AG as part of the experimental verification of the formulated hypothesis. Two different pixel structures were used in the four detectors, which is the silicon-only p-i-n diodes commonly found in literature and diode-connected SiGe heterojunction bipolar transistors (HBTs). These two categories can be subdivided into two more categories, which are the single-pixel-single-amplifier detectors and the multiple-pixel-single-amplifier detector. These were needed to assess the noise performance of different topologies. Noise influences both the DR and sensitivity of the detector. The results show a unique shift of the detecting band typically seen for silicon detectors to the IR band, accomplished by using the doping feature of HBTs using germanium. The shift in detecting band is from a peak of 250 nm to 665 nm. The detector still accumulates radiation in the visible band, but a significant portion of the near-IR band is also detected. This can be attributed to the reduced band gap energy that silicon with doped germanium exhibits. This, however, is not the optimum structure for IR detection. Future work that can be done based on this work is that the pixel structure can be optimised to move the detecting band even more into the IR region, and not just partially.Dissertation (MEng)--University of Pretoria, 2013.
Electrical, Electronic and Computer Engineering
unrestricted
38
Machhadani, Houssaine. "Transitions intersousbandes dans les puits quantiques GaN/AlN du proche infrarouge au THz." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00591962.
Full textAbstract:
Les transitions intersousbandes dans les hétérostructures de nitrure d'éléments III ont été intensément étudiées dans le proche infrarouge pour des applications télécoms. L'accordabilité dans le proche infrarouge est rendu possible grâce à la discontinuité de potentiel en bande de conduction qui peut atteindre 1.75 eV pour le système GaN/AlN. Les matériaux nitrures suscitent actuellement un grand intérêt à plus grande longueur d'onde infrarouge. C'est par exemple le développement de détecteurs et d'imageurs rapides à cascade quantique dans la gamme 2-5 µm. C'est aussi l'extension des dispositifs intersousbandes dans le domaine de fréquences THz. Ce travail de thèse porte sur l'étude des transitions intersousbandes dans les puits quantiques GaN/Al(Ga)N épitaxiés par jets moléculaires. Le but est d'accorder ces transitions dans une gamme spectrale très large allant du proche au lointain infrarouge. Je montre que les transitions ISB peuvent être accordées dans la gamme 1-12 µm dans les puits quantiques GaN/AlGaN en phase hexagonale synthétisés selon l'axe polaire c [0001]. Ceci impose l'ingénierie du champ électrique interne, dont la valeur peut atteindre dans le GaN 10 MV/cm. Une solution alternative consiste à utiliser une orientation particulière, dite semipolaire, qui conduit à une réduction du champ électrique interne le long de l'axe de croissance [11-22]. J'ai montré que cette réduction du champ interne permet d'accorder les résonances intersousbandes des puits quantiques GaN/AlN dans le proche infrarouge et j'ai pu estimer le champ en comparant les résultats de spectroscopie et simulations. J'ai d'autre part étudié les propriétés interbandes et intersousbandes des puits quantiques de symétrie cubique, qui par raison de symétrie, ne présentent pas de champ électrique interne. Finalement j'ai mis en évidence les premières transitions intersousbandes aux fréquences THz dans les puits quantiques GaN/AlGaN polaires mais aussi cubiques.
39
Kolahdouz, Esfahani Mohammadreza. "Application of SiGe(C) in high performance MOSFETs and infrared detectors." Doctoral thesis, KTH, Integrerade komponenter och kretsar, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-32049.
Full textAbstract:
Epitaxially grown SiGe(C) materials have a great importance for many device applications. In these applications, (strained or relaxed) SiGe(C) layers are grown either selectively on the active areas, or on the entire wafer. Epitaxy is a sensitive step in the device processing and choosing an appropriate thermal budget is crucial to avoid the dopant out–diffusion and strain relaxation. Strain is important for bandgap engineering in (SiGe/Si) heterostructures, and to increase the mobility of the carriers. An example for the latter application is implementing SiGe as the biaxially strained channel layer or in recessed source/drain (S/D) of pMOSFETs. For this case, SiGe is grown selectively in recessed S/D regions where the Si channel region experiences uniaxial strain.The main focus of this Ph.D. thesis is on developing the first empirical model for selective epitaxial growth of SiGe using SiH2Cl2, GeH4 and HCl precursors in a reduced pressure chemical vapor deposition (RPCVD) reactor. The model describes the growth kinetics and considers the contribution of each gas precursor in the gas–phase and surface reactions. In this way, the growth rate and Ge content of the SiGe layers grown on the patterned substrates can be calculated. The gas flow and temperature distribution were simulated in the CVD reactor and the results were exerted as input parameters for the diffusion of gas molecules through gas boundaries. Fick‟s law and the Langmuir isotherm theory (in non–equilibrium case) have been applied to estimate the real flow of impinging molecules. For a patterned substrate, the interactions between the chips were calculated using an established interaction theory. Overall, a good agreement between this model and the experimental data has been presented. This work provides, for the first time, a guideline for chip manufacturers who are implementing SiGe layers in the devices.The other focus of this thesis is to implement SiGe layers or dots as a thermistor material to detect infrared radiation. The result provides a fundamental understanding of noise sources and thermal response of SiGe/Si multilayer structures. Temperature coefficient of resistance (TCR) and noise voltage have been measured for different detector prototypes in terms of pixel size and multilayer designs. The performance of such structures was studied and optimized as a function of quantum well and Si barrier thickness (or dot size), number of periods in the SiGe/Si stack, Ge content and contact resistance. Both electrical and thermal responses of such detectors were sensitive to the quality of the epitaxial layers which was evaluated by the interfacial roughness and strain amount. The strain in SiGe material was carefully controlled in the meta–stable region by implementingivcarbon in multi quantum wells (MQWs) of SiGe(C)/Si(C). A state of the art thermistor material with TCR of 4.5 %/K for 100×100 μm2 pixel area and low noise constant (K1/f) value of 4.4×10-15 is presented. The outstanding performance of these devices is due to Ni silicide contacts, smooth interfaces, and high quality of multi quantum wells (MQWs) containing high Ge content.The novel idea of generating local strain using Ge multi quantum dots structures has also been studied. Ge dots were deposited at different growth temperatures in order to tune the intermixing of Si into Ge. The structures demonstrated a noise constant of 2×10-9 and TCR of 3.44%/K for pixel area of 70×70 μm2. These structures displayed an improvement in the TCR value compared to quantum well structures; however, strain relaxation and unevenness of the multi layer structures caused low signal–to–noise ratio. In this thesis, the physical importance of different design parameters of IR detectors has been quantified by using a statistical analysis. The factorial method has been applied to evaluate design parameters for IR detection improvements. Among design parameters, increasing the Ge content of SiGe quantum wells has the most significant effect on the measured TCR value.QC 20110405
40
Jollivet, Arnaud. "Dispositifs infrarouges à cascade quantique à base de semiconducteurs GaN/AlGaN et ZnO/ZnMgO." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS058/document.
Full textAbstract:
Ce mémoire de thèse est consacré à l’étude et au développement des hétérostructures semi-conductrices à base de GaN et ZnO. Ces matériaux sont particulièrement prometteurs pour le développement de composants optoélectroniques inter-sous-bandes infrarouges et notamment pour les dispositifs à cascade quantique. Ces semiconducteurs possèdent en effet plusieurs avantages pour la conception de dispositifs à cascade, tels qu’une grande discontinuité de potentiel en bande de conduction et une énergie du phonon LO très élevée. Ces propriétés se traduisent par la possibilité de développer des dispositifs couvrant une gamme spectrale allant du proche-infrarouge au térahertz et offrent la possibilité de réaliser des lasers à cascade quantique térahertz fonctionnant à température ambianteThis manuscript focuses on the study and on the development of semiconductor heterostructures based on GaN and ZnO material. These materials are particularly promising for the development of infrared optoelectronic intersubband devices in particular for quantum cascade devices. These semiconductors own several advantages to design quantum cascade devices such as a large conduction band offset and a large energy of the LO phonon. These properties predict the possibility to develop devices covering a large spectral range from near-infrared to terahertz and offer the possibility to realize terahertz quantum cascade lasers operating at room temperature
41
Chen, Lungway, and 陳龍威. "Image Evaluation and Analysis for AlInGaAs Quantum Well Detector." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/76402381169747708664.
Full textAbstract:
碩士國防大學理工學院
電子工程碩士班
101
In this thesis, the use of warm images of 320 × 256 variable measurement system FPA thermal imaging test and the physical properties of commonly used performance parameters description and laboratory measurements, including parameters such as SiTF, NETD, Uniformity, Operability, and addition, respectively, on eachdifferent band FPA parameters to adjust and optimize the image.Package before and after the test is also infrared focal plane arrays will be compared and the dead pixel compensation using MATLAB software image, making it more uniform screen. Can only be seen in the medium-wavelength image correction before the portrait unclear, good images can be obtained after correction of non-uniformity compensation and and its NEDT value of approximately 72mk Operability approximately 97%, Non-Uniformity of approximately 4%; however quantum wells advantage of it for long wavelength, so the development of a more mature, of its NEDT value of approximately 40mk Operability approximately 99%, Non-Uniformity of about 0.1%, and achieve the expected performance of the package after the image, can not only near-distance character imaging, and can be observed fine hair, Eye Movement and arm, blood vessels and other subtle temperature difference can be clearly ruled that, while the distant scene and high flying targets.
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Xu, Yuanjian. "Quantum well intersubband transition detection and modulation." Thesis, 1997. https://thesis.library.caltech.edu/1723/2/Xu_y_1997.pdf.
Full textAbstract:
This thesis is a theoretical and experimental investigation of the intersubband transitions in quantum well structures. The I-V characteristics, infrared absorption spectra, and photoresponse spectra of superlattices are used to characterize multiple quantum well structure properties in unipolar devices.
An important numerical method for solving the problem of bound-to-continuum transitions, the transfer matrix method, is presented for the self-consistent calculations. Although the boundary conditions are relaxed due to the calculation self-consistentcy, inappropriate boundary conditions were previously included in the literature.
The first observation of the quantum interference effect in the photocurrent spectra is described using a weakly coupled bound-to-continuum transition quantum well structure and electric field domain formation in the device. This effect persists even at high biases where Kronig-Penny minibands of periodic superlattice potential in the continuum are destroyed. Using this observation, the electric field domain formation and the electron coherence length in superlattices were analyzed. A large off-resonant energy level alignment between two neighboring wells in the high field domain was observed. The effect of temperature on the transport properties was also discussed. As a further study of electric field domain formation in superlattices, an optical experiment using Stark effect is suggested.
The dependence of the absorption spectral linewidth of quantum well intersubband transitions on the electron population in the well is experimentally demonstrated using field-induced charge transfer and thermal-induced charge transfer in an asymmetric coupled quantum well structure. We show that this population-induced broadening is very important in the broadening of intersubband transitions in quantum well structures and that previously reported linewidth values for the contribution from donor scattering were overestimated. Many body effects and single-particle band non-parabolicity are the likely causes. An electronic light chopper based on population modulation was fabricated using the asymmetric coupled quantum well structure. A modulation depth of 45% has been demonstrated using 50 periods of the coupled well structure.
43
Balakrishnam, Raju J. "Design, Fabrication And Characterization Of Corrugated-Quantum Well Infrared Photodetector." Thesis, 2005. http://etd.iisc.ernet.in/handle/2005/1426.
Full text
44
Deng, Shao You, and 鄧紹猷. "The Fabrication and Measurement of Muti-Quantum Well Infrared Detectors." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/44678454987787191253.
Full text
45
LAI, Ming-Chih, and 賴銘智. "Optimized Design of The Dual-band Quantum Well Infrared Detectors." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/84822993228291402826.
Full textAbstract:
碩士國防大學理工學院
光電工程碩士班
99
In this thesis, vertically stacked structure pixels combined with interlacemode achieves dual-band quantum well infrared detector elements, where it improvesthe shortcomings existing pixels on the process design, mask and components in the production of long-wavelength grating , the mask paste with the components and the gap between high and low when the shortcomings of this study, it improves the shortcomings of hight differences between mid- and long wavelength QWIP structure rusuiting in focusing on optical grating when the interlaced QWIPs are fabriouted. The study uses metal covered with the edge of Mid-wavelength QWIP to achieve the same height of dual-band QWIP, output Dual-band response and decrease device darkcurrent from surface and edge of QWIP. By proposed revised process.We improve the performance of interlanced dual-band QWIP. Where,it results in eages-undercuting and higher darkcurrent in our laboratory last year. Because the normal incident TE mode infrared light can not be adsorbed, the two-dimensioual optical grating must be used to deflect the incident light. The research is proposed a better parameters of two-dimensioual optical grating to apply the interlaced dual-band QWIPs. Using Comsol Multi-physics 3.5a simulator (fimite element method) combined with Schrodinger wave-equation, band-gap engineering in strained effect to optimize the period numbers, Al and In mole ratio of quantum well, QWIP stracture will be proposed efficiently and quickly.
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Jolley, Gregory. "Growth and analysis of quantum dots-in-a-well infrared photodetectors." Phd thesis, 2009. http://hdl.handle.net/1885/148261.
Full text
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"Control of transverse optical patterns in semiconductor quantum well microcavities." 2012. http://library.cuhk.edu.hk/record=b5549072.
Full textAbstract:
全光信息處理被認為是其中一種改善當今計算機網絡性能的方法。而高效率的全光信息處理需要使用可用低強度的控制激光來控制的全光學開關。最近有人提出利用橫向光學圖案製造低強度全光學開關，並已通過原子蒸氣系統的實驗證明這個計劃的可行性。此外，相關的研究正在半導體量子阱微腔中進行。這篇論文以微觀多體理論研究被激光正向入射的半導體量子阱微腔系統中產生的自發性橫向光學圖案。入射光會在一定條件下於半導體量子阱微腔中發生極化子場之間的自發四波混頻，並產生橫向光學圖案。我們分別以半分析和數值模擬的方法研究這些圖案的形成和選擇方式。本論文亦研究了如何用離軸激光和腔的各向異性來控制這些圖案。
我們分別用「多-
Processing information all-optically is thought to be one way to improve the performance of present-day computational network. Low intensity all-optical switches are desirable for effective all-optical information processing. Recently, low intensity all-optical switching schemes utilizing transverse optical patterns have been proposed. One such scheme was successfully demonstrated experimentally in an atomic vapour system, and a similar scheme is being studied both theoretically and experimentally in semiconductor quantum well micro-cavities.
In this thesis, we present our theoretical studies on the spontaneous transverse optical patterns produced by a semiconductor quantum well microcavity, pumped by a normally incident laser, using a microscopic many-body theory. Far field transverse optical patterns are formed under certain conditions by spontaneous four-wave mixing of the exciton-photon polariton field. The formation and the selection of these patterns are studied by both semi-analytical calculations and numerical simulations. The controls of transverse patterns using anisotropy in the microcavity and an o-axis control beam are also being studied in this thesis.
Two reduced models, the ‘multi-
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Luk, Ming Ho = 對半導體量子阱微腔中橫向光學圖案的控制 / 陸名浩.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2012.
Includes bibliographical references (leaves 136-141).
Abstracts also in Chinese.
Luk, Ming Ho = Dui ban dao ti liang zi jing wei qiang zhong heng xiang guang xue tu an de kong zhi / Lu Minghao.
Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Pattern formation and nonlinear optics --- p.5
Chapter 1.2 --- All-optical switching --- p.8
Chapter 1.3 --- Semiconductor quantum well microcavity --- p.9
Chapter 2 --- Semiconductor quantum well microcavity --- p.13
Chapter 2.1 --- The structure of semiconductor quantum well microcavity --- p.14
Chapter 2.2 --- Coupling between the cavity mode and external fields --- p.18
Chapter 2.3 --- Microscopic theory in the microcavity --- p.22
Chapter 3 --- Linear stability analysis and reduced models --- p.32
Chapter 3.1 --- Pump only system - steady state solution --- p.32
Chapter 3.2 --- Pump only system - stability analysis --- p.37
Chapter 3.3 --- Off-axis stability studies --- p.39
Chapter 3.3.1 --- Stability analysis without phase-space filling --- p.40
Chapter 3.3.2 --- Linear stability analysis with phase-space filling --- p.54
Chapter 3.4 --- Reduced models --- p.59
Chapter 3.4.1 --- The multi- --- p.63
Chapter 3.4.2 --- The ring model --- p.68
Chapter 3.5 --- Effects of system parameters --- p.71
Chapter 3.5.1 --- Radiative loss --- p.72
Chapter 3.5.2 --- Incident laser field/intensity --- p.73
Chapter 3.5.3 --- Fluctuations/weak constant sources --- p.78
Chapter 4 --- Single-hexagon model --- p.82
Chapter 4.1 --- Numerical results of single-hexagon model --- p.82
Chapter 4.2 --- Pattern and time scale variations with parameters --- p.86
Chapter 4.2.1 --- Anisotropy in the cavity mode energy --- p.87
Chapter 4.2.2 --- Control beam intensity --- p.90
Chapter 5 --- Dynamical analysis and interplay of wave-mixing processes --- p.93
Chapter 5.1 --- Dynamical analysis --- p.93
Chapter 5.2 --- Interplay of wave mixing processes --- p.99
Chapter 5.3 --- Switching between hexagons --- p.103
Chapter 6 --- Full two-dimensional simulation --- p.111
Chapter 6.1 --- Convolution theorem and Fast Fourier Transform --- p.112
Chapter 6.2 --- Simulation result and difficulties --- p.114
Chapter 7 --- Other approaches --- p.119
Chapter 7.1 --- Real Space Simulation --- p.119
Chapter 7.2 --- Mode competition model --- p.121
Chapter 7.3 --- Transfer Matrix --- p.123
Chapter 8 --- Conclusion and outlook --- p.125
Chapter 8.1 --- Future work --- p.128
Chapter 8.1.1 --- Double Cavities --- p.128
Chapter 8.1.2 --- The Gross-Pitaevskii Equation and Bose-Einstein Condensation --- p.131
Bibliography --- p.136
Chapter A --- Dispersion of cavity photon --- p.142
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En-Chih, Liu, and 劉恩池. "Investigations for the Dual-band Quantum Well Infrared Detectors Optimized under Process Condition." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/47779841567459400940.
Full textAbstract:
碩士國防大學理工學院
電子工程碩士班
100
The dissertation is to realize dual-band quantum well infrared detector elements by using stair structure to stack and interlace with pixels, further to improve the mid-wave structure of metalshort circuit during the interlace mode device process of current pixels. Due to the serious undercut, it has caused metal shutdown and could not to produce the long-wave photo response. The research is proposed to expose more metal short circuit mid - wave by stacking the stair structure, therefore successfully produces dual-band mid and long wave photo responses and increase photo responses and decrease dark current of devices. The research has improved and modified the previous dual band manufacturing process - the previous process had a low yield rate of lithography because it used different pictures during dual-band mid and long wave grating manufacturing process, which had led to a incomplete grating structure, therefore resulted in the degradation of dual band quantum well infrared detector . Because quantum well infrared detector elements can not absorb coupling positively reflecting Transverse Electric light, it is necessary to produce two-dimensioual optical grating on the devices. The research has obtained better two-dimension optical grating parameters and has successfully applied in the interlaced dual-band quantum well infrared detector elements.
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HUANG, YI-MIN, and 黃益民. "The design of tunable coupled quantum wells far-infrared detectors." Thesis, 1990. http://ndltd.ncl.edu.tw/handle/41460239391614177704.
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Lin, lian jium, and 李廉鈞. "Experiment emphasizes on the optimized design of the dual-band quantum well infrared detectors." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/55381961465161507164.
Full textAbstract:
碩士國防大學理工學院
電子工程碩士班
98
This experiment emphasizes on the optimized design of the dual-band quantum well infrared detectors.At first,required to achieve the better performance of to the single-band quantum well infrared detectors, based on optical and electrical properties analyzed optimization research to facilitate more effective coupling incident light from two-dimensional grating, as well as adjusting the position of potential energy wells, and carrier doping densities to improve the background of long-wavelength limit temperature, and other aspects. For single-band quantum well, the design dual-band quantum well after optimazing and the scheme of and process mask, the better design of wavelength absorption in the 4.7 μm and 8.4 μm, with the ranks of the exchange of detector is proposed. With the synchronous output is achieved under the middle and long-wavelength of and dual-band quantum well infrared detector, operating at 60 K, and a bias of -3.2 V.The dual-band response of the middle responsivity are 0.27 A/W and long wavelength responsivity are 0.39 A/ W.