Very high quantum efficiency in InAs/GaSb superlattice for very long wavelength detection with cutoff of 21 μm

• Published in: Applied physics letters Vol. 108; no. 12
• Main Authors: Jiang, Dongwei, Xiang, Wei, Guo, Fengyun, Hao, Hongyue, Han, Xi, Li, Xiaochao, Wang, Guowei, Xu, Yingqiang, Yu, Qingjiang, Niu, Zhichuan
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 21.03.2016
• Subjects: ABUNDANCE; Antireflection coatings; Applied physics; BERYLLIUM; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Cut off wavelength; Dependence; DETECTION; Doping; Efficiency; GALLIUM ANTIMONIDES; INDIUM ARSENIDES; Infrared detectors; PEAKS; Photovoltaic cells; QUANTUM EFFICIENCY; REFLECTION; SUPERLATTICES; WAVELENGTHS
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4944849

The authors report the dependence of the quantum efficiency on beryllium concentration in the active region of type-II InAs/GaSb superlattice infrared detector with a cutoff wavelength around 21 μm. It is found that the quantum efficiency and responsivity show a clear delineation in comparison to the doping concentration. The quantum efficiency is further improved by gradually doping in the absorbing region. At 77 K, the 50% cutoff wavelength of the VLWIR detector is 18 μm, and the R 0A is kept at a stable value of 6 Ω cm2. Different beryllium concentration leads to an increase of an average quantum efficiency in the 8–15 μm window from 35% to 55% with a π-region thickness of 3.0 μm, for U bias = −0.3 V, and no anti-reflection coating. As for a further result, the quantum efficiency reaches at a maximum value of 66% by gradually doping in the absorbing region with the peak detectivity of 3.33 × 1010 cm Hz1/2/W at 15 μm.