Single-crystalline bismuth sulfide microrods for efficient visible light photodetection

Abstract

Bismuth sulfide (Bi₂S₃) is a promising semiconductor with a direct bandgap of 1.3–1.7 eV and a high light absorption coefficient of approximately 10⁵ cm⁻¹, making it highly suitable for optoelectronic applications. A photoconductive device was fabricated by positioning a single Bi₂S₃ microrod between two Au electrodes on a SiO₂/Si substrate. The device demonstrates excellent performance, with a high switching ratio of 375, a responsivity of 69.76 A W⁻¹, an external quantum efficiency of 11 335%, and a detectivity of 8.95 × 10¹³ Jones under 765 nm monochromatic light at a 3 V bias. Additionally, the device features rapid response times, with rise and fall times of 122 ms and 128 ms, respectively. These results highlight the significant potential of Bi₂S₃ microrods in advancing photovoltaic and photodetection technologies.