Polarization-Sensitive Photodetector Based on High Crystallinity Quasi-1D BiSeI Nanowires Synthesized via Chemical Vapor Deposition.

Abstract

Bismuth chalcohalides (BiSeI and BiSI), a class of superior light absorbers, have recently garnered great attention owing to their promise in constructing next-generation optoelectronic devices. However, to date, the photodetection application of bismuth chalcohalides is still limited due to the challenge in controllable preparation. Herein, the synthesis of large-scale quasi-1D BiSeI nanowires via chemical vapor deposition growth is reported. By precisely tuning the growth temperature and the Se supply, it can effectively control the growth thermodynamics and kinetics of BiSeI crystal, and thus achieve high purity quasi-1D BiSeI nanowires with high crystal quality, uniform diameter, and tunable domain length. Theory and optical characterizations of the quasi-1D BiSeI nanowires reveal an indirect bandgap of 1.57eV with prominent optical linear dichroism. As a result, the quasi-1D BiSeI nanowire-based photodetector demonstrates a broadband photoresponse (400-800nm) with high responsivity of 5880mAW-1 , fast response speed of 0.11ms and superior air stability. More importantly, the photodetector displays strong polarization sensitivity (anisotropic ratio = 1.77) under the 532nm light irradiation. This work will provide important guides to the synthesis of other quais-1D metal chalcohalides and shed light on their potential in constructing novel multifunctional optoelectronic devices.