Download or read book Development of Multicolor Quantum Well Infrared Photodetector for Mid and Long wavelength Detection written by Jung-Chi Chiang and published by . This book was released on 1997 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Multi Color Quantum Well Infrared Photodetectors for Mid Long and Very Long Wavelength Infrared Applications written by Sheng S. Li and published by . This book was released on 2002 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum well infrared photodetectors (QWIPs) have been widely investigated for the 3 - 5 micrometers mid-wavelength infrared (MWIR) and 8 - 12 micrometers long-wavelength infrared (LWIR) atmospheric spectral windows as well as very long wavelength infrared (VLWIR: lambda(sub c)> 14 micrometers) detection in the past decade. The mature III-V compound semiconductor growth technology and the design flexibility of device structures have led to the rapid development of various QWIP structures for infrared focal plane arrays (FPAs) applications. In addition to the single-color QWIP with narrow bandwidth, the multi-color QWIP required for advanced IR sensing and imaging applications have also been emerged in recent years. Using band gap engineering approach, the multi-color (2, 3, and 4- color) QWIPs using multi-stack quantum wells with different well width and depth and voltage-tunable triple-coupled quantum well (TCQW) structure for detection in the MWIR, LWIR, and VLWIR bands have been demonstrated. In this paper, the design, fabrication, and characterization of a voltage-tunable 2-stack 3-color QWIP for MW/LW/LW IR detection and a 3-stack 3-color QWIP for detection in the water, ozone, and CO2 atmospheric blocking bands are depicted.
Download or read book Characterization and Analysis of a Multicolor Quantum Well Infrared Photodetector written by and published by . This book was released on 2006 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents analysis and characterization of performance of a newly designed, multicolor quantum well infrared photodetector (QWIP). Specifically, it focuses on a detector capable of detecting infrared emissions in the near infrared (NIR), mid-wavelength infrared (MWIR), and long-wavelength infrared (LWIR). Through photocurrent spectroscopy and performance analysis, this prototype detector can be classified and prepared for possible future use within the U.S. Armed Forces. Certain military applications require a highly accurate, reliable, sensitive, and multispectral infrared detector to identify targets and ensure mission success. By designing and fabricating a multicolor quantum well infrared photodetector, simultaneous detection of targets in the near infrared, mid-wavelength infrared and long-wavelength infrared is possible using only one detector. In addition, power and cooling requirements for quantum well infrared detectors makes them suitable for use in the field.
Download or read book Investigation of Multicolor and Simplified Quantum Well Infrared Photodetectors for MWIR and LWIR Detection written by and published by . This book was released on 2000 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this research program, we have investigated a four-stack, four-color quantum well infrared photodetector (QWIP), and studied the voltage distribution and temperature effect in this four-color QWIP. We have conducted a study on the quantum confined Stark-effect in an n-type QWIP. We have performed theoretical studies of the intersubband optical transitions in quantum dots and the design of GaAs/InGaAs and InAs/InAlAs quantum dot infrared photodetectors (QDIPs) for MWIR and LWIR detection. A new QWIP for very long wavelength infrared (VLWIR) applications has been investigated for 14-16 (micrometer) detection. Specific issues concerning device physics, detector design and device performance of the VLWIR QWIP are addressed. A VLWIR QWIP has been designed, fabricated and characterized. Two high performance multi-color, broadband QWIPs using digital graded superlattice barriers (DGSLB) for long wavelength infrared (LWIR) and broadband (BB) infrared detection have been demonstrated. We have also developed a high performance broadband (BB) In(0.26) Ga(0.74) As/Al(x) Ga(1-x)As QWIP using a linearly graded (LGB) Al(x) Ga(1-x) As barrier for LWIR detection. Theoretical study on the enhancement of quantum efficiency in a QWIP by using photonic crystal structure has also been carried out in this report.
Download or read book GUIA do produtor written by and published by . This book was released on 1996 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: Administração direta; Secretaria de política grícola-SPA; Abastecimento agropecuário; Secretaria de desenvolvimento rural-SDR; Assistência técnica e extensão rural; Conservação de solo e água; Cooperativismo e associativismo rural; Informação agrícola; Infra-estrutura rural; Mecanização e aviação agrícolas; Produção animal; Produção vegetal; Secretaria de defesa agropecuária-SDA; Defesa animal; Inspeção de produtos de origem animal; Defesa e inspeção vegetal; Endereços (EMATER, DEA, Convênios de classificação vegetal, Criadores de bovinos e laboratórios); Comissão especial de recursos-CER; Comissão executiva do plano da lavoura cacaueira-CEPLAC; Instituto naional de meteorologia-INMET; Administração indireta; Instituto nacional de colonização e reforma agrária-INCRA; Companhia Nacional de Abastecimento-CONAB; Empresa brasileira de pesquisa agropecuária -EMBRAPA; Companhia de colonização do nordeste-COLONE.
Download or read book Development of New III V Semiconductor Quantum Well Infrared Photodetectors for Mid and Long wavelength Infrared Detection written by Yanhua Wang and published by . This book was released on 1994 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation three types of III-V semiconductor quantum well infrared photodetectors (QWIPs) have been developed for 3-5 um mid-wavelength infrared (MWIR) and 8-14 um long-wavelength infrared (LWIR) detection. they are (1) GaAs/AlGaAs, GaAs/InGaP bound to continuum (BTC) QWIPs and InGaAs/InAlAs bound to miniband (BTM) QWIP, (2) nomral-incidence type II indirect bandgap AlAs/AlGaAs QWIP, and (3) normal incidence p-type strained layer InGaAS/InAlAs and InGaAs/GaAs QWIPs. These QWIP structures were grown by the molecular beam epitaxy (MBE) technique, with the exception of the GaAs/InGaP QWIP, which was grown by the metal-organic chemical vapor deposition (MOCVD) technique. Detectivity ranging from 10^9 to 10^12 cm-\/Hz/W was obtained for these QWIPs at T=77 K. The BTC and BTM QWIPs exhibited both photoconductive (PC) an photvoltain (PV) dual-mode (DM) detection characteristics. the peak wavelengths for the GaAs/AlGaAs QWIP were found to be at 7.7um and 12 um. The peak wavelengths for the GaAs/InGaP QWIP were found to be at 6.0um and 8.2 um. the voltage tunable InGaAs/InAlAs QWIP showed a peak wavelength of 10 um with dual-mode operation. a normal-incidence type II indirect bandgap AlAs/AlGaAs QWIP grown on (110)GaAS substrate was developed, which shows a multicolor detection feature with peak response wavelengths occurred at 2.2, 2.7, 3.5, 4.8, 6.5, and 12.5 um. Extremely large photo-conductivity gains of 630 and 3200 at peak wavelengths of 3.5 and 2.2 um were obtained at Vb=3 and 6 V, respectively, while a broad spectral photoresponse with peak wavelength at 12.5 um was observed. A normal-incidence p-type tensile strained-layer InGaAs/InAlAs QWIP grown on InP substrate with an ultralow dark current density (about six orders of magnitude smaller than the standard GaAs/AlGaAs QWIP) was developed in this work. this QWIP has achieved background limited performance (BLIP) for T
Download or read book Quantum Well Infrared Photodetectors written by Harald Schneider and published by Springer. This book was released on 2006-10-18 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: Addressed to both students as a learning text and scientists/engineers as a reference, this book discusses the physics and applications of quantum-well infrared photodetectors (QWIPs). It is assumed that the reader has a basic background in quantum mechanics, solid-state physics, and semiconductor devices. To make this book as widely accessible as possible, the treatment and presentation of the materials is simple and straightforward. The topics for the book were chosen by the following criteria: they must be well-established and understood; and they should have been, or potentially will be, used in practical applications. The monograph discusses most aspects relevant for the field but omits, at the same time, detailed discussions of specialized topics such as the valence-band quantum wells.
Download or read book Development of High Performance Multicolor Quantum Well Infrared Photodetectors and Studies of Enhancing Light Coupling and Radiation Effects in QWIPs written by and published by . This book was released on 1999 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this report, we present the design, fabrication, and characterization of several high performance multi-color and broadband quantum well infrared photodetectors (QWIPs) for both MWIR and LWIR applications. The report covers tasks performed during the period from March 3, 1998 through July 10, 1999. A very high sensitivity, high-strain, multi-color triple-coupled (TC-) QWIP using InGaAs/AlGaAs/InGaAs material systems has been developed in this project for LWIR multi-color detection. A two-stack InGaAs/AlGaAs/InGaAs TC-QWIP and InGaAs/AlGaAs TC-QWIP has been developed for the LWIR and MWIR dual-band detection. In addition, a high-strain InGaAs/GaAs TC-QWIP with and without two-dimensional (2-D) grating coupler has been designed, fabricated, and characterized for the LWIR detection. This device shows very high responsivity under 450 back-illumination. Several broadband (BB-) QWIPs have been developed for the LWIR detection. These include (1) two-stack, five-well n-type InGaAs/AlGaAs broadband (BB-) QWIPs with 3- and 7-period QWs in the unit cell, (2) 3- and 4-well n-type BB-QWIPs, and (3) two 3- and 4- well p-type BB-QWIPs. In addition, a three-stack InGaAs/AlGaAs/InGaAs BB TC-QWIP grown on GaAs substrate has been developed for LWIR detection, which has a FWHM spectral bandwidth twice larger than the single-stack TC-QWIP. Finally, a MWIR InGaAs/InAlAs TC-QWIP grown on InP substrate, operating up to T = 116K with excellent device performance, has also been demonstrated. Four journal papers and six conference papers have been published and presented from this work.
Download or read book Investigation of High Performance Multicolor Quantum Well Infrared Photodetectors and 4 X 4 Three color Focal Plane Array for Mid and Long wavelength Applications written by Jung Hee Lee and published by . This book was released on 2000 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mid Wavelength Quantum Well Infrared Photodetectors written by and published by . This book was released on 1998 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum-well infrared photodetectors (QWIPs) have developed rapidly over the past ten years. Most of the efforts have been concentrated on the longwavelength and the very-long-wavelength regions of the thermal emission spectrum. Due to the success of InSb, HgCdTe, and PtSi detectors in the midwavelength infrared region, less emphasis has been placed on the development of QWIP focal-plane arrays operating in this wavelength band. However, recent interest in establishing pixel-registered, multispectral imaging capabilities has emphasized the need for high-quality mid-wavelength detectors that can be integrated with long-wavelength devices. In this presentation, the design and characterization of QWIPs using InGaAs/AlGaAs grown on GaAs substrates and InGaAs/InAlAs grown on InP substrates will be discussed. Both of these material systems can be used as single-wavelength, mid-wave devices and are compatible with vertical integration to give multispectral operation. Fundamental detector parameters, such as optical absorption strength, photoconductive gain, and temperature-dependent dark current, have been determined for various midwavelength QWIP designs and will be presented along with the results of singlepixel radiometric tests.
Download or read book Growth and Fabrication of Multi Quantum Well Infrared Photodetectors written by and published by . This book was released on 2000 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: A majority of infrared sensors used for imaging arrays operating in the long-wavelength infrared region between lambda = 8-12 micrometers are based on HgCdTe. This material system is unable to satisfy all of the requirements that are imposed by modern applications. Structural difficulties due to poor uniformity, high defect densities, and weak bond strengths cause difficulties in manufacturing large infrared focal plane array cameras. As an alternative, quantum well infrared photodetectors (QWIPs) utilizing intersubband absorption between GaAs wells and AlGaAs barriers were perfected. These QWIPs possess better uniformity in comparison to HgCdTe detectors, and QWIP imaging arrays have recently become commercially available. However, the responsivity of GaAs/AlGaAs QWIPs is still lower than HgCdTe detectors. In order to further improve the responsivity of QWIP detectors, the development of QWIPs with wells or barriers of OaInAsP instead of MOaAs has been developed.
Download or read book Multicolor Quantum Well Infrared Photodetectors written by Meimei Tidrow and published by . This book was released on 1998 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multicolor infrared (IR) detectors are very important to advanced IR sensor systems. An IR detector with multicolor capability can offer a better target discrimination, tracking, and identification, as well as temperature determination. Multicolor IR sensors are also very useful in industry for gas leakage detection, chemical analysis, and for environmental sensing and control. As the IR technology continues to advance, there is a growing demand of multicolor IR detectors for advanced IR sensor systems. Quantum well infrared photodetector (QWIP) is one of the competing technologies that shows very promising potential in infrared detection and imaging. One major advantage of QWIPs is its multicolor detection capability and voltage tunability. Several approaches of achieving multicolor detection, detailed device structures, and performance of multicolor QWIPs will be presented. The multicolor voltage tunability, simultaneous detection capability, and the Stark Shift effect for fine tuning of the peak detection wavelength will be discussed.
Download or read book Advanced Luminescent Materials and Quantum Confinement written by M. Cahay and published by The Electrochemical Society. This book was released on 1999 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Two Color Photodetector Using an Asymmetric Quantum Well Structure written by Kevin R. Lantz and published by . This book was released on 2002-06 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past twenty years have seen an explosion in the realm of infrared detection technology fueled by improvements in III-V semiconductor technology and by new semiconductor growth methods. One of the fastest growing areas of this research involves the use of bandgap engineering in order to create artificial quantum wells for use in Quantum Well Infrared Photodetectors (QWIPs) . QWIPs have an advantage over other infrared detectors such as Mercury Cadmium Telluride (MCT) because they have larger bandgaps and are therefore stronger and cheaper to manufacture. This thesis introduces one method of multi-color' detection through the use of an asymmetries quantum well structure in which all energy transitions are possible. The QWIP structure in this thesis was designed to detect a laser wavelength of 1.06 micrometers and a wavelength in the 8-10 micrometers atmosphere window. The relevance of a detector that is tuned to these wavelengths is that it can be used on military aircraft as a laser spot tracker and an infrared imager providing much greater accuracy and dependability than older systems.
Download or read book High Responsivity Tunable Step Quantum Well Infrared Photodetector written by Yeo Hwee Tiong and published by . This book was released on 2004-12-01 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, the performance of a step quantum well infrared photodetector (QWIP), which was designed to detect a laser spot at 1.05 m and IR radiation between 9.5 m to 10.5 m, was evaluated. In the far infrared (FIR), the maximum responsivity of the test detector at 10 K was measured at 1.02 A/W with a peak wavelength of 10.3 m under a negative bias of 0.83 V. The D* at background limited infrared performance (BLIP) was measured at 8.0x10(9) cm square root Hz/W with 180 degrees field of view. The BLIP temperature was found to be about 55 K. In addition, the FIR detection wavelength found shift with the amount of bias across the device. The amount of shift observed was 0.21 meV/ kvcm-1 which is due to linear Stark effect associated with the step quantum well. The quantum well infrared detectors made of square quantum wells found to have an order of magnitude lower Stark shift originated from second order effects. This suggests that the step well infrared detector can have applications in tunable wavelength infrared detectors.
Download or read book Image Smearing in a Quantum Well Infrared Photodetector Monolithically Integrated With a Light Emitting Diode written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The recent advances in infrared sensing technology has made it possible to use infrared sensors to support environmental observations, surveillance, threat detection, tracking, and target identification. For ballistic missile defence (BMD) related applications, the most important detector requirements are: high sensitivity, high uniformity, large format, and multicolor capabilities. Quantum well infrared photodetector (QWIP) is a relatively new candidate technology for BMD applications. It has become one of the most promising near-term infrared technologies to meet mid-course detection requirements because of its wavelength flexibility in mid-infrared, far-infrared, and very far-infrared regions, as well as multicolor capabilities. Canadian QWIP technology is based on monolithic integration of quantum well infrared photodetector with a light emitting diode (QWIP-LED), and was pioneered by Dr. H.C. Liu of Institute for Microstructural Sciences, National Research Council of Canada. The goal of the present program is to realize a 1x1 sq cm(exp 2) two-color QWIP-LED imaging device by March 2001 and, eventually, to develop a very large format (up to 4x4 sq cm(exp 2)) prototype imaging camera. The success of the QWIP-LED depends critically on the extent of spatial lateral spreading of both photocurrent generated in the QWIP and near infrared photons emitted by the LED as they escape from the QWIP-LED layers. According to a LED model proposed by Schnitzer et al., there appears to be a trade-off between a high LED external quantum efficiency and a small photon lateral spread, the former being a necessary condition for achieving high detector sensitivity. The model predicts that as much as 25 reincarnations of the originally emitted NIR photons (as they spread laterally within the QWIP-LED) are required for most of the LED emitted light to escape.
Download or read book Mid infrared Semiconductor Optoelectronics written by Anthony Krier and published by Springer. This book was released on 2007-05-22 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optoelectronic devices operating in the mid-infrared wavelength range offer applications in a variety of areas from environmental gas monitoring around oil rigs to the detection of narcotics. They could also be used for free-space optical communications, thermal imaging applications and the development of "homeland security" measures. Mid-infrared Semiconductor Optoelectronics is an overview of the current status and technological development in this rapidly emerging area; the basic physics, some of the problems facing the design engineer and a comparison of possible solutions are laid out; the different lasers used as sources for mid-infrared technology are considered; recent work in detectors is reviewed; the last part of the book is concerned with applications. With a world-wide authorship of experts working in many mid-infrared-related fields this book will be an invaluable reference for researchers and graduate students drawn from physics, electronic and electrical engineering and materials science.
