Bulk InAsSb-based upside-down pCBn photodetectors with greater than 5 µm cut-off wavelength

• Published in: AIP advances 2022-05, Vol.12 (5), p.055327-055327-6
• Main Authors: Chen, Dongqiong, Li, Dexiang, Xiao, Tingting, Shi, Jingmei, He, Yan, Gong, Xiaoxia, Yang, Shaopei, Yue, Biao, Zhao, Jun, Yang, Wenyun, Deng, Gongrong
• Format: Article
• Language: English
• Subjects: Cut off wavelength; Dark current; Operating temperature; Photometers; Quantum efficiency
• ISSN: 2158-3226; 2158-3226
• DOI: 10.1063/5.0093335

The InAsSb-based photodetectors covering the whole mid-infrared wavelength at 150 K have been modeled, successfully fabricated, and characterized. In this work, we increased the Sb composition in InAs1−xSbx to extend the cut-off wavelength; simultaneously, the novel upside-down structure was adopted to decrease the dark current to ensure good performance of the device at high operating temperature. The growth sequence of the upside-down InAs0.81Sb0.19/AlAsSb material system was reversed to the conventional nBn structure, and the AlSb/AlAs0.08Sb0.92 electron compound barrier was grown before the InAs0.81Sb0.19 active layer. At 150 K and 0.8 V forward bias, the fabricated photodetector demonstrates a dark current density around 3.46 × 10−4 A/cm2, a peak responsivity up to 1.89 A/W, and a quantum efficiency up to 56% at 4.2 µm, corresponding to 1.23 × 1011 cm Hz1/2/W detectivity.