Mid-IR type-II InAs/GaSb nanoscale superlattice sensors
type: CreativeWork
description: The detection of mid-wavelength infrared radiation (MWIR) is very important for many military, industrial and biomedical applications. Present-day commercially available uncooled IR sensors operating in MWIR region (2-5μm) use microbolometric detectors which are inherently slow. Available photon detectors (mercury cadmium telluride (MCT), bulk InSb and quantum well infrared detectors (QWIPs))overcome this limitation. However, there are some fundamental issues decreasing their performance and ability for high temperature operation, including fast Auger recombination rates and high thermal generation rate. These detectors operate at low temperatures (77K-200K) in order to obtain high signal to noise ratio. The requirement of cooling limits the lifetime, increases the weight and the total cost, as well as the power budget, of the whole infrared system. In recent years, InAs/GaSb superlattice based detectors have appeared as an interesting alternative to the present-day IR detector systems. These heterostructures have a type-II band alignment such that the conduction band of InAs layer is lower than the valence band of GaSb layer. The effective bandgap of these structures can be adjusted from 0.4 eV to values below 0.1 eV by varying the thickness of constituent layers leading to an enormous range of detector cutoff wavelengths (3-30μm). The InAs/GaSb SLs have a higher degree of uniformity than the MCT alloys, making them attractive for large area focal plane arrays. They provide a smaller leakage current due to larger effective electron mass, which suppresses tunneling. This material system is also characterized by high operating temperatures and long Auger recombination rates. This suggests the potential for using the SLs technology for realizing high operating temperature devices. This work is focused on the development of mid-IR InAs/GaSb SLs sensors with high-operating temperature. Contributions of this thesis include 1) development of growth and processing procedur…
abstract: The detection of mid-wavelength infrared radiation (MWIR) is very important for many military, industrial and biomedical applications. Present-day commercially available uncooled IR sensors operating in MWIR region (2-5μm) use microbolometric detectors which are inherently slow. Available photon detectors (mercury cadmium telluride (MCT), bulk InSb and quantum well infrared detectors (QWIPs))overcome this limitation. However, there are some fundamental issues decreasing their performance and ability for high temperature operation, including fast Auger recombination rates and high thermal generation rate. These detectors operate at low temperatures (77K-200K) in order to obtain high signal to noise ratio. The requirement of cooling limits the lifetime, increases the weight and the total cost, as well as the power budget, of the whole infrared system. In recent years, InAs/GaSb superlattice based detectors have appeared as an interesting alternative to the present-day IR detector systems. These heterostructures have a type-II band alignment such that the conduction band of InAs layer is lower than the valence band of GaSb layer. The effective bandgap of these structures can be adjusted from 0.4 eV to values below 0.1 eV by varying the thickness of constituent layers leading to an enormous range of detector cutoff wavelengths (3-30μm). The InAs/GaSb SLs have a higher degree of uniformity than the MCT alloys, making them attractive for large area focal plane arrays. They provide a smaller leakage current due to larger effective electron mass, which suppresses tunneling. This material system is also characterized by high operating temperatures and long Auger recombination rates. This suggests the potential for using the SLs technology for realizing high operating temperature devices. This work is focused on the development of mid-IR InAs/GaSb SLs sensors with high-operating temperature. Contributions of this thesis include 1) development of growth and processing procedur…
author: Plis, Elena A.
language: English
keywords: Infrared detectors--Materials, Superlattices as materials
date published: 2007-09-09T07:00:00Z
date modified: 2026-07-24T05:27:25Z
provider: University of New Mexico
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of New Mexico