Self-Powered Photodetector of Bi0.5Sb1.5Te3/Si with Ultrafast Response

Bi0.5Sb1.5Te3 (BST) has attracted much attention owing to its special physical properties, including strong surface carrier mobility and narrow band gap. In this study, the photoelectric performance of the photodetector based on BST/Si heterojunctions was systematically investigated. Our photodetector accomplishes a large self-powered position sensitivity (405 mV/mm) and a detectivity of 3.1 × 1011 Jones. The relaxation times of the lateral photovoltaic voltage reached 0.106 μs. The BST/Si heterojunction achieves broad-spectrum photodetection covering a spectrum from visible light to the infrared wavelength range, with a photoelectrical bandwidth exceeding 15 kHz. This research demonstrates the considerable potential of ultrafast response photodetectors for self-powered position-sensitive detectors, imaging, and object recognition in future.