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 Intersubband Transitions in Quantum Wells Physics and Devices written by Sheng S. Li and published by Springer Science & Business Media. This book was released on 2013-11-27 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: The International Workshop on "Intersubband Transitions in Quantum Wells:: Physics and Applications," was held at National Cheng Kung University, in Tainan, Taiwan, December 15-18, 1997. The objective of the Workshop is to facilitate the presentation and discussion of the recent results in theoretical, experimental, and applied aspects of intersubband transitions in quantum wells and dots. The program followed the tradition initiated at the 1991 conference in Cargese-France, the 1993 conference in Whistler, B. C. Canada, and the 1995 conference in Kibbutz Ginosar, Israel. Intersubband transitions in quantum wells and quantum dots have attracted considerable attention in recent years, mainly due to the promise of various applications in the mid- and far-infrared regions (2-30 J. lm). Over 40 invited and contributed papers were presented in this four-day workshop, with topics covered most aspects of the intersubband transition phenomena including: the basic intersubband transition processes, multiquantum well infrared photodetector (QWIP) physics, large format (640x480) GaAs QWIP (with 9. 0 J. lffi cutoff) focal plane arrays (FPAs) for IR imaging camera applications, infrared modulation, intersubband emission including mid- and long- wavelength quantum cascade (QC) lasers such as short (A. "" 3. 4 J. lm) and long (A. "" 11. 5 J. lm) wavelength room temperature QC lasers, quantum fountain intersubband laser at 15. 5 J. lm wavelength in GaAs/AIGaAs quantum well, harmonic generation and nonlinear effects, ultra-fast phenomena such as terahertz (THz) intersubband emission and detection. The book divides into five Chapters.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Lithographically Patterned Quantum Dot Structures for Infrared Detection written by and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Significant progress was made to further advance the quantum well infrared photodetector (QWIP) technology in two areas: 1) designing, demonstrating, and understanding voltage tunable two-color QWIPs, and 2) understanding the light coupling mechanism in the so-called quantum grid infrared photo-detectors. We have also been working on imprint technology to create pillars which can be used to enhance the performance of the photo detectors. The NIL molds with different period and different shape of the pillars have been created. Implementation of the small pillars to photo detectors are in progress.

Download or read book Quantum Dot Photodetectors written by Xin Tong and published by Springer Nature. This book was released on 2021-09-17 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a comprehensive overview of state-of-the-art quantum dot photodetectors, including device fabrication technologies, optical engineering/manipulation strategies, and emerging photodetectors with building blocks of novel quantum dots (e.g. perovskite) as well as their hybrid structured (e.g. 0D/2D) materials. Semiconductor quantum dots have attracted much attention due to their unique quantum confinement effect, which allows for the facile tuning of optical properties that are promising for next-generation optoelectronic applications. Among these remarkable properties are large absorption coefficient, high photosensitivity, and tunable optical spectrum from ultraviolet/visible to infrared region, all of which are very attractive and favorable for photodetection applications. The book covers both fundamental and frontier research in order to stimulate readers' interests in developing novel ideas for semiconductor photodetectors at the center of future developments in materials science, nanofabrication technology and device commercialization. The book provides a knowledge sharing platform and can be used as a reference for researchers working in the fields of photonics, materials science, and nanodevices.

Download or read book Seeing Photons written by National Research Council and published by National Academies Press. This book was released on 2010-09-28 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Department of Defense recently highlighted intelligence, surveillance, and reconnaissance (ISR) capabilities as a top priority for U.S. warfighters. Contributions provided by ISR assets in the operational theaters in Iraq and Afghanistan have been widely documented in press reporting. While the United States continues to increase investments in ISR capabilities, other nations not friendly to the United States will continue to seek countermeasures to U.S. capabilities. The Technology Warning Division of the Defense Intelligence Agency's (DIA) Defense Warning Office (DWO) has the critical responsibility, in collaborations with other components of the intelligence community (IC), for providing U.S. policymakers insight into technological developments that may impact future U.S. warfighting capabilities. To this end, the IC requested that the National Research Council (NRC) investigate and report on key visible and infrared detector technologies, with potential military utility, that are likely to be developed in the next 10-15 years. This study is the eighth in a series sponsored by the DWO and executed under the auspices of the NRC TIGER (Technology Insight-Gauge, Evaluate, and Review) Standing Committee.

Download or read book Asymmetric Quantum Well Structures for Enhanced Infrared Photon Absorption written by Mehjabeen Akhtar Khan and published by . This book was released on 2013 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: Compared to inter-band transition for photon absorption in a quantum wells, intra-band (or inter-subband) transitions in heterojunction (GaAs/InP) quantum wells can provide access to a broader range of wavelengths for detector design, specifically detectors operating in the mid infrared region of spectrum (4-12 [micro]m) and beyond is possible. These quantum wells not only provide great flexibility in optimizing the Eigen energy levels or wavefunctions, and inter-subband optical matrix elements determining the corresponding transition probability, but also allow controlling electron-phonon scattering rates and thus electron lifetime. The research presented in this dissertation investigates asymmetric quantum well structures formed through III-V semiconductor material system such as AlGaAs/ InxGa(1-x)As/InyGa(1-y) As/AlGaAs that can further improve the responsivity through higher carrier mobility. Asymmetry is introduced by using multiple materials to form the well region. The advantage of exploring stepped quantum well structure stems from experimental evidence that such structures are capable of absorbing normal incidence and thus eliminates the requirement of incorporating additional optical coupling schemes such as grating structures. An important contribution of this research is the development of an analytical model to analyze single or multiple quantum well structures to quantify photon absorption. The physical model developed in this work is based on non-equilibrium Green's function (NEGF), Fermi's golden rule and quantum mechanical wave impedance concept. The approach has two distinct advantages. First, it is accurate, easily programmable and yet computationally efficient. Second, it facilitates quantifying the broadening of states resulting from both photon absorption and tunneling, which provides important insight for improving detection efficiency. Instead of being presented through calculations, such broadening has been simply assumed in previously reported works. The method developed in this research provides an efficient methodology to quantify the absorption rate of photons with different polarizations. The study looks into the design and analysis of the wells to enhance infrared radiation detection, and suggests mechanisms to optimize the structures in terms of material choice, composition, structural geometry and applied voltages. The high electron mobility and hence drift velocity in InGaAs ( >5×106cm/s), along with low carrier recapture lifetime, is expected to improve the detection speed of the device. Unlike GaAs/AlGaAs, the lattice mismatch at InGaAs/AlGaAs interface is likely to introduce strain in the structure. The effect of such strain as well as the layer thickness is taken into account in this work. Also, a methodology for achieving voltage tenability, i.e. the ability to detect different wavelengths at different bias voltages has been investigated. Although both n-type and p-type systems have potential for optoelectronic devices, n-type quantum wells are more advantageous because of their nearly parabolic sub-band structure. As for material consideration, direct band gap material based systems, such as AlGaAs/InGaAs and AlGaAs/GaAs, have been found to be particularly suitable for n-type QWIP photodetectors. The reason being that the electrons in such materials occupy states around the [gamma]valley where the effective mass is smaller and therefore mobility is higher; a condition which leads to higher photoresponsivity. Moreover such systems allow the possibility of highly stable device operation owing to the insensitivity of intra-band transition energies to temperature fluctuation and reduced influence of Auger recombination.

Download or read book Structural Optical and Spectral Behaviour of InAs based Quantum Dot Heterostructures written by Saumya Sengupta and published by Springer. This book was released on 2017-08-19 with total page 59 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores the effects of growth pause or ripening time on the properties of quantum dots(QDs). It covers the effects of post-growth rapid thermal annealing (RTA) treatment on properties of single layer QDs. The effects of post-growth rapid thermal annealing (RTA) treatment on properties of single layer QDs are discussed. The book offers insight into InAs/GaAs bilayer QD heterostructures with very thin spacer layers and discusses minimum spacer thickness required to grow electronically coupled bilayer QD heterostructures. These techniques make bilayer QD heterostructures a better choice over the single layer and uncoupled multilayer QD heterostructure. Finally, the book discusses sub-monolayer (SML) growth technique to grow QDs. This recent technique has been proven to improve the device performance significantly. The contents of this monograph will prove useful to researchers and professionals alike.

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1995 with total page 876 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Handbook of Self Assembled Semiconductor Nanostructures for Novel Devices in Photonics and Electronics written by Mohamed Henini and published by Elsevier Science. This book was released on 2008 with total page 841 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1969, Leo Esaki (1973 Nobel Laureate) and Ray Tsu from IBM, USA, proposed research on “man-made crystals” using a semiconductor superlattice (a semiconductor structure comprising several alternating ultra-thin layers of semiconductor materials with different properties). This invention was perhaps the first proposal to advocate the engineering of a new semiconductor material, and triggered a wide spectrum of experimental and theoretical investigations. However, the study of what are now called low dimensional structures (LDS) began in the late 1970's when sufficiently thin epitaxial layers were first produced following developments in the technology of epitaxial growth of semiconductors, mainly pioneered in industrial laboratories for device purposes. The LDS are materials structures whose dimensions are comparable with inter-atomic distances in solids (i.e. nanometre, nm). Their electronic properties are significantly different from the same material in bulk form. These properties are changed by quantum effects. At the inception of their investigation it was already clear that such structures were of great scientific interest and excitement and their novel properties caused by quantum effects offered potential for application in new devices. Moreover these complex LDS offer device engineers new design opportunities for tailor-made new generation electronic devices. The LDS could be considered as a new branch of condensed matter physics because of the large variety of possible structures and the changes in the physical processes. One of the promising fabrication methods to produce and study structures with a dimension less than two such as quantum wires and quantum dots, in order to realise novel devices that make use of low-dimensional confinement effects, is self-organisation. Self-assembled nanostructured materials offer a number of advantages over conventional material technologies in a wide-range of sectors. Clearly, future research work on self-assembled nanostructures will connect diverse areas of material science, physics, chemistry, electronics and optoelectronics. Key Features: - Contributors are world leaders in the field - Brings together all the factors which are essential in self-organisation of quantum nanostructures - Reviews the current status of research and development in self-organised nanostructured materials - Provides a ready source of information on a wide range of topics - Useful to any scientist who is involved in nanotechnology - Excellent starting point for workers entering the field - Serves as an excellent reference manual

Download or read book Electrical Electronics Abstracts written by and published by . This book was released on 1997 with total page 1948 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Physics Of Quantum Well Infrared Photodetectors written by Kwong-kit Choi and published by World Scientific. This book was released on 1997-06-12 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past, infrared imaging has been used exclusively for military applications. In fact, it can also be useful in a wide range of scientific and commercial applications. However, its wide spread use was impeded by the scarcity of the imaging systems and its high cost. Recently, there is an emerging infrared technology based on quantum well intersubband transition in III-V compound semiconductors. With the new technology, these impedances can be eliminated and a new era of infrared imaging is in sight. This book is designed to give a systematic description on the underlying physics of the new detectors and other issues related to infrared imaging.

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 Antimonide based Infrared Detectors written by Antoni Rogalski and published by . This book was released on 2018 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Among the many materials investigated in the infrared (IR) field, narrow-gap semiconductors are the most important in IR photon detector family. Although the first widely used narrow-gap materials were lead salts (during the 1950s, IR detectors were built using single-element-cooled PbS and PbSe photoconductive detectors, primary for anti-missile seekers), this semiconductor family was not well distinguished. This situation seems to have resulted from two reasons: the preparation process of lead salt photoconductive polycrystalline detectors was not well understood and could only be reproduced with well-tried recipes; and the theory of narrow-gap semiconductor bandgap structure was not well known for correct interpretation of the measured transport and photoelectrical properties of these materials"--

Download or read book Long Wavelength Infrared Detectors written by Manijeh Razeghi and published by CRC Press. This book was released on 2020-03-09 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: This timely work presents a comprehensive overview of the development of new generations of infrared detectors based on artificially synthesized quantum structures. The growth of quantum wells and superlattices is well documents in this volume, as are the principal new superlattice technologies for long wavelength infrared detection. Featuring insightful contributions from researchers working at the "cutting edge" of this exciting field, this volume is sure to become an essential reference for advanced graduate students and researchers alike.

Download or read book Advances in Infrared Photodetectors written by and published by Elsevier. This book was released on 2011-05-03 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. Originally widely known as the "Willardson and Beer" Series, it has succeeded in publishing numerous landmark volumes and chapters. The series publishes timely, highly relevant volumes intended for long-term impact and reflecting the truly interdisciplinary nature of the field. The volumes in Semiconductors and Semimetals have been and will continue to be of great interest to physicists, chemists, materials scientists, and device engineers in academia, scientific laboratories and modern industry. Written and edited by internationally renowned experts Relevant to a wide readership: physicists, chemists, materials scientists, and device engineers in academia, scientific laboratories and modern industry