Design and optimization of the performance of self-powered Sb2S3 photodetector by SCAPS-1D simulation and potential application in imaging

Abstract

Antimony sulfide (Sb2S3) is considered an excellent semiconductor material for visible light photodetectors (PDs) due to the non-toxicity, stability and high visible photon absorption coefficient. However, the deep physical cascade relationship between Sb2S3 devices and key parameters, such as the thickness, the doping density, the defect density, and the inverse contact of the figure of merit, has not been thoroughly investigated. In order to systematically explore the impact of parameters on Sb2S3 device performance, self-powered optoelectronic devices of TiO2/Sb2S3 p-n heterojunction were simulated by using one-dimensional (SCAPS-1D) software. Base on simulation, we learned that the optimum thickness of Sb2S3 is about 400 nm, the donor and acceptor densities of TiO2 and Sb2S3 layers are 1020 and 1016 cm−3, respectively. In addition, Au was chosen as the back electrode, and the high-quality Sb2S3 functional layer required a defect density of less than 1016 cm−3. Based on the guidance of simulation results, we finally fabricated the FTO/TiO2/Sb2S3/Au self-powered photodetectors. Under an illumination intensity of 3 μW/cm2 at 530 nm, the responsivity (R) and specific detectivity (D*) of the device can be up to 0.357 A/W and 5.1 × 1011 Jones, respectively. Particularly, the device exhibits a fast response with a response time of 1.4 μs and 3 dB bandwidth of 383 kHz. In this regard, we constructed a single-pixel scanning imaging system around the Sb2S3 detector and showed excellent imaging results, which provided a new path for us to develop a new type of visible light detector and imaging system.