Theory and Experiment of Antimony-based Type-II Superlattice Infrared Photodetectors

Theory and Experiment of Antimony-based Type-II Superlattice Infrared Photodetectors PDF Author: Shin Mou
Publisher: ProQuest
ISBN: 9780549341161
Category :
Languages : en
Pages : 110

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There is currently considerable interest in InAs/InGaSb type-II superlattices because of their broken-gap type-II band alignment, which forms spatially indirect band gaps in the range of 3--30 mum. Combining the advantages of III-V epitaxial growth techniques and high sensitivity to normal incident light, the InAs/InGaSb superlattice is a promising material system for the next generation of mid-infrared photodetector focal plane arrays (FPAs). In order to understand the underlying physics and to improve the device performance of this emerging technique, InAs/InGaSb superlattice photodetectors are studied theoretically and experimentally in this dissertation. First, an eight-band k · p method is developed to model the band structures and absorption coefficient. The calculated absorption coefficient spectra agree very well with our experimental curves, validating the effectiveness of the eight-band k · p method. Second, quantum efficiency (QE), an important figure of merit for infrared photodetectors, is analyzed by an analytical model based on absorption coefficient and transport parameters (e.g., minority carrier diffusion length) obtained by electron beam induced current (EBIC) technique. By successfully modeling the QE of InAs/GaSb superlattice photodiodes, we ensure that the depletion region in InAs/GaSb superlattice photodiodes is effective in collecting the photoexcited carriers. Understanding the dark current mechanisms of InAs/GaSb superlattice photodiodes is another important task when the surface leakage current is detrimental. We use an analytical model, which explains successfully the measured I-V curves. With the observation of a sinh(qV/4KT) dependence under small forward bias, a surface channel current model originally developed by Sah is used to explain the surface leakage current of InAs/GaSb superlattice photodiodes for the first time. Besides the conventional photodiodes, we take advantage of the InAs-(In)GaSb-Al(In)Sb nearly lattice-matched system to design novel antimony-based type-II photodetectors based on our eight-band k · p method. After interband cascade detectors with promising room temperature performance (dynamic impedance and area product (R0A) equals to 22 Ocm2 at 300 K) are obtained, a new design for interband tunneling detectors is introduced. With a thicker active region, the QE of interband tunneling detectors is improved more than five times compared to that of interband cascade detectors.

Theory and Experiment of Antimony-based Type-II Superlattice Infrared Photodetectors

Theory and Experiment of Antimony-based Type-II Superlattice Infrared Photodetectors PDF Author: Shin Mou
Publisher: ProQuest
ISBN: 9780549341161
Category :
Languages : en
Pages : 110

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Book Description
There is currently considerable interest in InAs/InGaSb type-II superlattices because of their broken-gap type-II band alignment, which forms spatially indirect band gaps in the range of 3--30 mum. Combining the advantages of III-V epitaxial growth techniques and high sensitivity to normal incident light, the InAs/InGaSb superlattice is a promising material system for the next generation of mid-infrared photodetector focal plane arrays (FPAs). In order to understand the underlying physics and to improve the device performance of this emerging technique, InAs/InGaSb superlattice photodetectors are studied theoretically and experimentally in this dissertation. First, an eight-band k · p method is developed to model the band structures and absorption coefficient. The calculated absorption coefficient spectra agree very well with our experimental curves, validating the effectiveness of the eight-band k · p method. Second, quantum efficiency (QE), an important figure of merit for infrared photodetectors, is analyzed by an analytical model based on absorption coefficient and transport parameters (e.g., minority carrier diffusion length) obtained by electron beam induced current (EBIC) technique. By successfully modeling the QE of InAs/GaSb superlattice photodiodes, we ensure that the depletion region in InAs/GaSb superlattice photodiodes is effective in collecting the photoexcited carriers. Understanding the dark current mechanisms of InAs/GaSb superlattice photodiodes is another important task when the surface leakage current is detrimental. We use an analytical model, which explains successfully the measured I-V curves. With the observation of a sinh(qV/4KT) dependence under small forward bias, a surface channel current model originally developed by Sah is used to explain the surface leakage current of InAs/GaSb superlattice photodiodes for the first time. Besides the conventional photodiodes, we take advantage of the InAs-(In)GaSb-Al(In)Sb nearly lattice-matched system to design novel antimony-based type-II photodetectors based on our eight-band k · p method. After interband cascade detectors with promising room temperature performance (dynamic impedance and area product (R0A) equals to 22 Ocm2 at 300 K) are obtained, a new design for interband tunneling detectors is introduced. With a thicker active region, the QE of interband tunneling detectors is improved more than five times compared to that of interband cascade detectors.

Characterization of Antimony-based Type-II Superlattice Infrared Photodetectors

Characterization of Antimony-based Type-II Superlattice Infrared Photodetectors PDF Author: Qi Lou
Publisher:
ISBN:
Category :
Languages : en
Pages : 82

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Antimony-based Type-II Superlattice Infrared Detectors

Antimony-based Type-II Superlattice Infrared Detectors PDF Author: Martin Mandl
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Numerous applications within the mid- and long-wavelength infrared are driving the search for efficient and cost effective detection technologies in this regime. Theoretical calculations have predicted high performance for InAs/GaSb type-II superlattice structures, which rely on mature growth of III-V semiconductors and offer many levels of freedom in design due to band structure engineering. This work focuses on the fabrication and characterization of type-II superlattice infrared detectors. Standard UV-based photolithography was used combined with chemical wet or dry etching techniques in order to fabricate antinomy-based type-II superlattice infrared detectors. Subsequently, Fourier transform infrared spectroscopy and radiometric techniques were applied for optical characterization in order to obtain a detector's spectrum and response, as well as the overall detectivity in combination with electrical characterization. Temperature dependent electrical characterization was used to extract information about the limiting dark current processes. This work resulted in the first demonstration of an InAs/GaSb type-II superlattice infrared photodetector grown by metalorganic chemical vapor deposition. A peak detectivity of 1.6x10^9 Jones at 78 K was achieved for this device with a 11 micrometer zero cutoff wavelength. Furthermore the interband tunneling detector designed for the mid-wavelength infrared regime was studied. Similar results to those previously published were obtained.

Antimony-based Type-II Superlattice Infrared Photodetectors on Indium-arsenide Substrates

Antimony-based Type-II Superlattice Infrared Photodetectors on Indium-arsenide Substrates PDF Author: Daniel Y. Zuo
Publisher:
ISBN:
Category :
Languages : en
Pages :

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The wide variety of applications for mid- and far-infrared detection has spurred the study of cutting-edge technologies for use in the next genera- tion of detectors in place of the current systems, such as mercury cadmium telluride. While type-II superlattices over a number of advantages in design and material quality, theoretical predictions of their high performance have yet to be realized. This work concentrates on novel designs, fabrication, and characterization of type-II superlattice infrared detectors. In this work we present the first InAs/GaSb type-II superlattice photode- tectors grown on an InAs substrate via metal-organic chemical vapor depo- sition. The design and fabrication of the devices are detailed, along with several characterization processes, including low-temperature electron beam induced current (EBIC) to study structural defects. Through this work, the optical absorption of the undoped substrate was shown to be significantly lower than that of GaSb. The detectors have a cutoff wavelength (50% re- sponsivity) of 9.5 um at 78 K. Their R0A values are on the order of 10^-2 Ohm*cm2. The typical peak responsivity is 1.9 A/W, and the devices have a peak detectivity of 6.8 * 10^9 cm*Hz^1/2 /W at 78 K.

Theory and Experiments of Type-II Superlattice Infrared Photodetectors

Theory and Experiments of Type-II Superlattice Infrared Photodetectors PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Dissertation Abstracts International

Dissertation Abstracts International PDF Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 946

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Infrared Detectors

Infrared Detectors PDF Author: Antonio Rogalski
Publisher: CRC Press
ISBN: 1420076728
Category : Science
Languages : en
Pages : 900

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Book Description
Completely revised and reorganized while retaining the approachable style of the first edition, Infrared Detectors, Second Edition addresses the latest developments in the science and technology of infrared (IR) detection. Antoni Rogalski, an internationally recognized pioneer in the field, covers the comprehensive range of subjects necessary to un

Fundamental Research on Infrared Detection

Fundamental Research on Infrared Detection PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 31

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Book Description
Fundamental research issues on infrared photodetectors are reported. These include the following: Task 1. HgCdTe (MCT) defect study Continuing the research on degradation of MCT, we explore the size changing of the dislocation loops and the effect of low-dose electron beam irradiation during TEM analysis. Self-energy correction is included to calculate the MCT defect states. For the photoluminescence image, we correlate the PL images from MCTs and their CZT substrates. Task 2. Antimony-based type-II superlattice (T2-SL) photodetectors We explored the temperature dependent and noise current characteristics of interband cascade detectors (ICDs). We also acquired type-II superlattice photodiodes from Jet Propulsion Lab and obtained a high detectivity of 5.23x1010 cmHz1/2/W at 77 K with devices of 10.5 m cutoff wavelength. Moreover, MOCVD growth of InAs/GaSb type-II superlattices was explored with substrates of both GaSb and GaAs. Task 3. Quantum dot infrared photodetectors (QDIPs) Our work has been focused on the growth and fabrication of high performance QDIP devices based on technologies developed. Defect-free 100-period InAs QD structure has been demonstrated. For InAs QDIPs grown on InP substrates by molecular beam epitaxy (MBE), peak detectivity of 2.1x109 cmHz1/2/W was achieved at a bias voltage of 0.8V.

Materials Science and Technology: Strained-Layer Superlattices

Materials Science and Technology: Strained-Layer Superlattices PDF Author:
Publisher: Academic Press
ISBN: 0080864309
Category : Technology & Engineering
Languages : en
Pages : 443

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Book Description
The following blurb to be used for the AP Report and ATI only as both volumes will not appear together there.****Strained-layer superlattices have been developed as an important new form of semiconducting material with applications in integrated electro-optics and electronics. Edited by a pioneer in the field, Thomas Pearsall, this volume offers a comprehensive discussion of strained-layer superlattices and focuses on fabrication technology and applications of the material. This volume combines with Volume 32, Strained-Layer Superlattices: Physics, in this series to cover a broad spectrum of topics, including molecular beam epitaxy, quantum wells and superlattices, strain-effects in semiconductors, optical and electrical properties of semiconductors, and semiconductor devices.****The following previously approved blurb is to be used in all other direct mail and advertising as both volumes will be promoted together.****Strained-layer superlattices have been developed as an important new form of semiconducting material with applications in integrated electro-optics and electronics. Edited by a pioneer in the field, Thomas Pearsall, this two-volume survey offers a comprehensive discussion of the physics of strained-layer superlattices (Volume 32), as well as detailing fabrication technology and applications of the material (Volume 33). Although each volume is edited to stand alone, the two books combine to cover a broad spectrum of topics, including molecular beam epitaxy, quantum wells and superlattices, strain-effects in semiconductors, optical and electrical properties of semiconductors, and semiconductor devices.

Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 836

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