Chemically deposited Sn？doped PbS thin films for infrared photodetector applications

Abstract

Lead sulfde is a potential infrared (IR) photodetector material because of its favorable optoelectronic properties. The physical and chemical properties of PbS can be modifed by a systematic doping of elements. In this study, we have doped 1？3 at% of Sn into PbS by a chemical bath deposition method. The undoped PbS flms exhibited cubic crystal structure with a lattice parameter of a = 0.594 nm, an uneven grain growth, a direct optical band gap of 0.44 eV and a hole mobility of 8.9 cm2 V？1 s？1. The Sn-doping has improved the microstructure and slightly decreased the band gap of PbS. The hole mobility of PbS flms has increased to 20 cm2 V？1 s？1 with Sn-doping (1？2 at%). Thus, the PbS flms grown by Sn-doping with improved microstructure, decreased band gap, and increased electrical properties are benefcial for IR photodetector applications.