Characterization of Antimony-based Type-II Superlattice Infrared Photodetectors PDF Download
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Author: Qi Lou
Publisher:
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Category :
Languages : en
Pages : 82
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Author: Qi Lou
Publisher:
ISBN:
Category :
Languages : en
Pages : 82
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Author: Martin Mandl
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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.
Author: Daniel Y. Zuo
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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.
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.
Author: Priyanka Petluru
Publisher:
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Category :
Languages : en
Pages : 0
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Photodetectors operating in the mid-infrared wavelength range have traditionally been dominated by the HgCdTe (MCT) material system. However, there has been growing interest in other materials due to environmental concerns regarding the toxicity of both mercury and cadmium, as well as issues with the non-uniformity of MCT epitaxial growth and minimal MCT fabrication infrastructure, compared to that of traditional arsenic- and antimony-based III-V material systems. One such example is the type-II superlattice (T2SL), which has shown great potential due to its theoretically predicted advantages such as suppressed Auger recombination, as well as for its bandgap flexibility. Yet at longer wavelengths, superlattices show weaker absorption coefficients compared to bulk materials. One option to address this deficiency is to utilize optical engineering to overcome the decreased absorption of T2SLs at these wavelengths, leveraging phenomena such as plasmonic structures. Highly doped semiconductors can act as plasmonic materials in the mid-infrared, allowing for monolithic integration of these materials into optoelectronic device structures. In this work, several all-epitaxial structures are discussed, highlighting the capabilities of integrated highly doped semiconductor materials, as well as the potential of T2SLs as an absorber material, for next generation infrared photodetectors. The first example is an all-epitaxial dielectric-metal-dielectric structure capable of supporting long-range surface plasmon polaritons in the long-wave infrared, with type-II superlattices (T2SLs) utilized as the dielectric layers in this structure. Additionally, a thin long-wave infrared p-i-n detector designed for enhanced absorption at band-edge, utilizing a guided mode resonance, is investigated. Furthermore, a detector operating at 180K in the long-wave infrared, utilizing a resonant cavity, and configured for focal plane arrays, is demonstrated. The absorption peak for this detector can be spectrally tuned across the long wave infrared wavelength range by changing the total cavity thickness, and experimental results show an external quantum efficiency of 25% on resonance at 10.8μm. Another possible alternative to the HgCdTe material system is a quaternary alloy such as InAsSbBi, which also offers large design flexibility without a weaker absorption coefficient. The potential of InAsSbBi as an absorber material for infrared detectors is also investigated, through photoluminescence and minority carrier lifetime measurements. Finally, future work and potential new directions for these projects are discussed. In particular, possible methods to improve the optical and electrical characteristics of the resonant cavity enhanced detectors are included
Author:
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ISBN:
Category :
Languages : en
Pages : 31
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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.
Author:
Publisher: Elsevier
ISBN: 0123813387
Category : Science
Languages : en
Pages : 385
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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
Author: Narae Yoon
Publisher:
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Category :
Languages : en
Pages : 302
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Author: Bradley J. Rawlins
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Category :
Languages : en
Pages : 90
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Author: Erick John Michel
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Category :
Languages : en
Pages :
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