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

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 x 10(-4) A/cm(2), a peak responsivity up to 1.89 A/W, and a quantum efficiency up to 56% at 4.2 mu m, corresponding to 1.23 x 10(11) cm Hz(1/2)/W detectivity. (C) 2022 Author(s).