Download or read book GaAs A1GaAs Quantum Well Infrared Photodetectors QWIPs Utilizing Intersubband Transitions ISBTs written by Krishna Simkhada and published by . This book was released on 2011 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Intersubband Transitions in Quantum Wells Physics and Devices written by Sheng S. Li and published by Springer. This book was released on 2011-10-08 with total page 214 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 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 Multi Band GaAs AlGaAs Quantum Well Infrared Photodetector QWIP Focal Plane Arrays written by and published by . This book was released on 2002 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The GaAs/AlGaAs based Quantum Well Infrared Photodetectors (QWIPs) afford greater flexibility than the usual extrinsically doped semiconductor IR detectors because the wavelength of the peak response and cutoff can be continuously tailored over any wavelength between 6-20 micrometers. The spectral band width of these detectors can be tuned from narrow (DELTAlamba/lamba ^ 10 %) to wide (DELTAlamba/lamba ^ 50 %) allowing various applications. Also, QWIP offers multi-color infrared cameras which is capable of simultaneously acquiring images in different infrared bands. Each pixel of such array consists of vertically stacked, independently readable, QWIP detectors sensitive in different narrow infrared bands. In this article, we discuss the development and results of the 640x512 dual-band and four-band QWIP FPAs.

Download or read book Quantum Structure Infrared Photodetectors written by Riccardo Introzzi and published by LAP Lambert Academic Publishing. This book was released on 2010-07 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum structure Infrared Photoetectors (QsIPs) are based on Intersubband transitions. GaAs mature technology makes Quantum Well Infrared Photodetectors (QWIPs) very attractive for their flexibility to enhanced device functionality and ease of integration with optoelectronic devices. Quantum Dot Infrared Photodetectors (QDIPs), based on 3-D confinement, are an evolution of QWIPs. They are expected to achieve higher detectivities. Charge transport has been investigated by current noise analysis, on QWIPs and QDIPs. Peculiar dynamics, beyond the expectations of noise models in literature, have been evidenced experimentally in QWIPs. An analytical model, based on a Langevin approach, has been developed and qualitatively reproduced real noise spectra. QDIP high performances have been hampered, so far, by homogeneity lack in self-assemble growing technology. Photoresponsivity and Noise spectra were found closely related to quantum dot inhomogeneity. Further insights has been added in the complex new phenomena observed in QDIPs. This work should help specialists as well anyone else who may be interested in better understanding the complex physics of QsIPs and the investigation methods.

Download or read book Confined Electrons and Photons written by Elias Burstein and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 900 pages. Available in PDF, EPUB and Kindle. Book excerpt: The optical properties of semiconductors have played an important role since the identification of semiconductors as "small" bandgap materials in the thinies, due both to their fundamental interest as a class of solids baving specific optical propenies and to their many important applications. On the former aspect we can cite the fundamental edge absorption and its assignment to direct or indirect transitions, many-body effects as revealed by exciton formation and photoconductivity. On the latter aspect, large-scale applications sucb as LEDs and lasers, photovoltaic converters, photodetectors, electro-optics and non-linear optic devices, come to mind. The eighties saw a revitalization of the whole field due to the advent of heterostructures of lower-dimensionality, mainly two-dimensional quantum wells, which through their enhanced photon-matter interaction yielded new devices with unsurpassed performance. Although many of the basic phenomena were evidenced through the seventies, it was this impact on applications which in turn led to such a massive investment in fabrication tools, thanks to which many new structures and materials were studied, yielding funher advances in fundamental physics.

Download or read book Physics of Quantum Well and Quantum Dot Infrared Photodetectors written by V. Ryzhii and published by . This book was released on 2000 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: We review the recent studies of physical effects in quantum well and quantum dot infrared photodetectors utilizing intersubband transitions.

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 AlGaAs GaAs Quantum Well Infrared Photodetectors written by Michael A. Dem'yanenko and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Observation of Quantum Confined Stark Effect in Triple Coupled InGaAs GaAs AlGaAs Quantum Well Infrared Photodetector written by and published by . This book was released on 1997 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have investigated the quantum-confined Stark effect (QCSE) in several n-type InGaAs/GaAs/AlGaAs triple-coupled quantum well infrared photodetectors (TC-QWIPs) for 8-12 micrometers long wavelength infrared (LWIR) detection. The basic structure of this TC-QWIP consists of three coupled quantum wells (QWs) formed by a Si-doped In(x)Ga(1-x)As QW and two undoped thin GaAs QWs separated by two thin Al(y)Ga(1-y)As barriers. Three TC-QWIP devices with varying indium and aluminum compositions were fabricated and characterized. A strong QCSE for the (E1 to E3) transition was observed in the wavelength range of 8.2 - 9.1 micrometers, 10.8 - 11.5 micrometers, and 9.4 - 10.7 micrometers for QWIP-A, -B, and -C, respectively. These devices exhibit a linear dependence of peak wavelength on the applied bias voltage over these wavelengths ranges. Peak responsivities, R(1) = 0.05, 0.33 A/W and detectivities, D*(BLIP) = 6.1x10(exp9), l.63x10(exp10)cm-Hz(1/2)/W at V(b)=5, 4 V, lamba(p)=8.6, 11.2 micrometers, and T(BLIP)=66, 50 K were obtained for QWIP-A and -B, respectively. For QWIP-C, R(1)=0.19 A/W was obtained at lamba(p)=9.3 micrometers, V(b)=7 V, and T+60 K.

Download or read book Pjse o Theofilowi na geho swatb Angel Rafael byl a kterak od n ho zase k rozkossjm ragsk m gsa pozw n 360 let tam bydlel written by and published by . This book was released on 1775 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Intersubband Transitions in Quantum Well Infrared Photodetector written by Chin Wei Cheah and published by . This book was released on 2001 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book GaIn As P GaAs Very Long Wavelength QWIP written by and published by . This book was released on 2000 with total page 62 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 structural difficulties due to poor uniformity, high defect densities, and weak bond strengths that 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 GaInAsP instead of AlGaAs has been developed. Results of detector characterization are presented for QWIPs fabricated from a variety of III-V material systems including GaAs/GaInP, GaInAs/InP, AlGaInAs/InP, and GaInAs/AlInAs. These material systems extend the range of sensitivity from 3-20 micrometers while remaining lattice-matched to InP. Also, lattice-matched multispectral detectors are demonstrated for sensitivity at both 4 micrometers and 8.5 micrometers. The ultimate objective is to produce a monolithically integrated QWIP focal plane array on Si substrate.

Download or read book Investigation of Normal Incident High Performance P type Strained Layer InGaAs AlGaAs and GaAs AlGaAs Quantum Well Infrared Photodetectors written by and published by . This book was released on 1995 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have made excellent progress towards the program goals. A significant achievement was made in the development of a new compressively strained p-type InGaAs/AlGaAs QWIP grown on GaAs by MBE with very low dark current densities. This new QWIP achieved two color detection with detection peaks at 7.4 micrometers in the LWIR band and 5.5 micrometers in the MWIR band. This detector is under background limited performance (BLIP) at temperatures up to 67 K, with operation possible at temperatures greater than 85 K. The measured responsivity was found to be 40 mA/W for the LWIR peak, while a responsivity of 8 mA/W was found for the MWIR peak; all at T=77 K. In addition, the measured detectivity was found to be 1.06 x 10(exp 10) Jones at T=81 K and 1.0 V of applied bias. In addition, two new compressively strained p-QWIPs with detection peaks at 9.2 micrometers and 10.1 micrometers were characterized. Responsivities of 28 mA/W at T=45 K and V=-2.5 V and 1% mA/W at T=55 K and -1.0 V were measured at the 9.2 micrometers and 10.1 micrometers peaks respectively. The 9.2 micrometers p-QWIP has an estimated D* of 2.7 x 1O(exp 9) Jones, while the 10.1 micrometers peak p-QWIP has an estimated D*-of 1.04 x 10(exp 9) Jones. Finally, a Si-doped unstrained p-QWIP grown on (311) Si GaAs was characterized. This p-QWIP exhibits extremely symmetrical dark current characteristics and has two MWIR detective peaks at 3.0 micrometers and 5.2 micrometers. jg p.2.

Download or read book Ultra fast Antenna coupled Mid infrared Quantum well Photodetectors written by Quyang Lin and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Thesis is devoted to the conception, fabrication and experimental characterization of semiconductor-based ultra-fast photodetectors operating in the mid-infrared range (~3-12um). More specifically, the detectors that I have developed, generally known as multi-quantum-well infrared photodetectors (QWIPs), rely on intersubband (ISB) transitions in a GaAs-Al_0.2Ga_0.8As heterostructure, where an electron occupying the ground state of a quantum-well is photoexcited into an upper state, lying next to the energy continuum above the AlGaAs barriers.In my work I have exploited a specific device geometry that allows light-coupling at normal incidence, based on a two-dimensional array of electrically connected metallic patch-antennas. Each antenna is obtained by sandwiching the GaAs-AlGaAs multi-quantum-well heterostructure between a top contact metal layer and a bottom metallic ground plane, effectively forming a square metal-dielectric-metal microcavity, where the fundamental TM electromagnetic mode is resonant with the energy of the ISB transition. Finally, to allow for broadband microwave extraction, the antenna array is connected to a 50Ohm, monolithically integrated coplanar waveguide.In the first part of my work I have designed the antennas for optimum detection at 10um wavelength. This was done by running a set of simulations using a commercial electromagnetic solver based on the finite-difference time-domain (FDTD) method. Based on the results of the simulations I have fabricated a set of preliminary structures, without coplanar waveguide, to characterize the optical properties of the antenna array through Fourier transform micro-reflectance measurements. These measurements have allowed me to select the optimum patch array dimensions, namely the lateral size of the square-patch and the array periodicity.The second part of my work has been dedicated to the fabrication of the complete QWIP detector, including the monolithically integrated coplanar waveguide. In these detectors the size of the two-dimensional antenna array has been kept to a minimum, without compromising the radiation collection, in order to reduce as much as possible the device parasitic RC time constant and therefore maximize the detector speed. I have fabricated two generations of detectors relying on two slightly different active regions, respectively based on a bound-to-bound and a bound-to-continuum design. In the final part of my PhD I have also fabricated a third generation of devices, where the patch array, rather than to a coplanar waveguide, is connected to a spiral THz antenna. This device has not been characterized in this work and I present its relevance in the context of this Thesis in the perspectives.The last part of the Thesis is dedicated to the electro-optical characterization of the fabricated detectors. First, I have measured the dark current, the polarization dependence, and the dc photoresponse, that allowed me to determine the responsivity at 77K and 300K. Then I characterized the microwave frequency response of the detectors. To this end I have participated to the setup of an experimental apparatus based a high-speed (67GHz) cryogenic probe station. In this apparatus the beams of two quantum cascade lasers (QCLs) emitting at 10.3um wavelength, are simultaneously focused on the QWIP detector to generate a hererodyne signal at their difference frequency. By temperature/current tuning the emission wavelength of one QCL the heterodyne frequency can be swept continuously, thus allowing the measurement of the detector frequency response with the help of a spectrum analyzer. At room-temperature I obtain a flat frequency response up to 70GHz, solely limited by the bandwidth of the acquisition electronics. This is the broadest RF- bandwidth reported to date for a QWIP photodetector. To analyze the experimental data, I have modelled the electrical behavior of the QWIP using a small-signal equivalent circuit model.

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.