Double barrier strained quantum well infrared photodetectors for the 3–5μm atmospheric window

Abstract

We present a detailed study of double barrier strained Al0.35Ga0.65As/AlAs/GaAs/In0.2Ga0.8As quantum well infrared photodetectors on GaAs substrate. Measurements were made on four different well widths active layers and on several mesa pixels with different optical coupling structures. We obtained responses peaked in the spectral range 3.6–4.6 μm. Based on the experimental results, we show that in the background limited regime, the impact ionization is the restrictive transport process for midwave detectors. We also demonstrate a 4 μm structure with the high background limited detectivity of 2×1011 Jones at 77 K and 9×1010 Jones at 110 K (2π field of view, 300 K background).

Mid-wave QWIPs for the [3–4.2μm] atmospheric window

“…QWIPs have also been demonstrated at 4.9 lm with the InGaAs/InGaP heterostructure on InP [5], and at 5.5 lm with InGaAs/AlGaAsP on GaAs [6]. on GaAs [12]. We report a strong influence of the segregation process on the composition profile and on the electrical characteristics.…”

“…The second approach for detection in the [3-4.2 lm] spectral range is based on DBS QWIP [12]. The samples were grown on semi-insulating GaAs (0 0 1) substrate, using molecular beam epitaxy (RIBER 49 system).…”

“…Quantum Well Infrared Photodetectors (QWIPs) have been widely investigated for detection in the long-wave (LW) infrared [8][9][10][11][12][13][14] lm] region of the infrared spectrum [1]. Their specific advantages (GaAs-based III-V materials, easy wavelength adjustment, high thermal stability, high uniformity and yield, no low-frequency noise) established them as high performance detectors for third generation infrared cameras.…”

Structural and chemical study of AlGaAs/InGaAs based QWIPs

“…Due to localized states, the quantum well properties are highly sensitive to the shape of the confining potential and to the quality of the surrounding materials. This is particularly the case for the so called DBS (Double Barrier Strained) [4] QWIPs which employ sub-nanometer layers.…”

Influence of doping on the performance of GaAs/AlGaAs QWIP for long wavelength applications

“…Recently, GaAs−based QWIP has emerged as one of the most promising photodetectors for infrared (IR) imaging application in the Long Wavelength (LW) IR region [11]. Advantages of GaAs−based QWIP include easy wavelength adjustment, high thermal salability and high uniformity which recognized them as high performance detectors for third generation infrared cameras [12]. In addition, GaAs/ Al x Ga 1-x As based QWIPs can be designed for various appli− cations by controlling Al composition in AlGaAs layer and by controlling thickness of this layer [13].…”