PbS/ Si NW Heterojunction on Silicon Chip Based Self-Powered Photo Detector Device for IR Radiations by Chemical Bath Deposition

Heterojunction device based on 1D Si NW and PbS are gaining increasing attention as they are expected to extend the detection wavelength towards near infra-red region for silicon integrated optical devices. In this work, PbS-Si NW heterostructure thin films were fabricated through chemical bath deposition in presence of tri sodium citrate as the complexing agent. The growth conditions viz. time, temperature and the presence of the citrate are found to have an immense influence on the device efficiency. Under optimized growth condition, the device was found to generate a photocurrent of ~ 2.5µA and a photovoltage of ~ 50 mV at 0 V bias (self-powered mode). The device recorded a maximum responsivity of ~ 0.21 A/W and detectivity ~ 6*10⁹ Jones under an illumination of 1064 nm and an intensity of 0.3 mW/cm² in self-powered mode. These results indicate a potential low cost, effective experimental technique for synthesis of PbS-Si NW for self-powered photodetector application.