Synthesis of bismuth sulfide nanobelts for high performance broadband photodetectors†
Broadband photodetectors are critical to modern industrial systems and scientific applications and have attracted broad attention in recent years. In this paper, high quality single-crystal Bi2S3 nanobelts were prepared by using the chemical vapor deposition (CVD) method. The Bi2S3 nanobelts were further used as photosensitive materials for broadband photo-detection. The as-grown Bi2S3 nanobelts exhibit ultrahigh absorption coefficiency in the ultraviolet (UV) to near infrared (NIR) range. The photodetectors based on a single Bi2S3 nanobelt showed excellent broadband photoresponse performance in the UV to NIR range (from 300 to 1000 nm), including high photoresponsivity up to 201 A W−1, an ultrafast response speed of ∼50 μs, a high external quantum efficiency of 31 140% and a high detectivity of 2.7 × 1010 Jones. The superior performance can be attributed to the ultrahigh absorption coefficiency of Bi2S3 nanobelts, as well as the Schottky contact between the Bi2S3 nanobelt and the Au electrode. The present work suggests that the single-crystal Bi2S3 nanobelts possess great potential for the fabrication of high performance broadband photodetectors.