Preparation and characterization of In0.82Ga0.18As PIN photodetectors

Abstract

Using two-step growth method and buffer layer annealing treatment, the double heterojunction structures of In0.82Ga0.18As epilayer capped with InAs0.6P0.4 layer were prepared on InP substrate by low pressure metal organic chemical vapor deposition (LP-MOCVD). Based on the high quality In0.82Ga0.18As structures, the In0.82Ga0.18As PIN photodetector with cut-off wavelength of 2.56 μm at room temperature was fabricated by planar semiconductor technology, and the device performance was investigated in detail. The typical dark current at the reverse bias V R=10 mV and the resistance area product R 0 A are 5.02 μA and 0.29 Ω·cm2 at 296 K and 5.98 nA and 405.2 Ω·cm2 at 116 K, respectively. The calculated peak detectivities of the In0.82Ga0.18As photodetector are 1.21×1010 cm·Hz1/2/W at 296 K and 4.39×1011 cm·Hz1/2/W at 116 K respectively, where the quantum efficiency η=0.7 at peak wavelength is supposed. The results show that the detection performance of In0.82Ga0.18As prepared by two-step growth method can be improved greatly.