Ultrasensitive and broad-spectrum polarization sensitive photodetector based on individual Bi2Te0.6S2.4 nanobelt

Abstract

Polarimetric photodetectors with broadband and fast response have important applications in the military and civilian fields. Alloying of semiconductors is a good strategy to regulate its electronic band structure which broadens the photoresponse range of the corresponding optoelectronic devices. In this work, we designed and grew the high-quality Bi2Te0.6S2.4 alloy via controllable chemical vapor transport. The as-prepared Bi2Te0.6S2.4 nanobelts were designed to work as the active layer in photodetectors. The individual Bi2Te0.6S2.4 nanobelt based photodetector exhibits excellent photoresponse properties in a broadband range from solar-blind ultraviolet-C (254 nm) to near-infrared (1064 nm) with a good responsivity of 340 mA/W, a specific detectivity of 2.3 × 109 Jones, and extremely low dark current (1.1 pA). The photodetectors also exhibit a fast response speed of about 1 μs which comes from the direct transition of carriers in Bi2Te0.6S2.4 confirmed by the Ohmic contact between Bi2Te0.6S2.4 and electrodes. Furthermore, it is worth noting that the Bi2Te0.6S2.4 nanobelts have high polarization sensitivity in the broadband ranges from 266 to 1064 nm with the maximum dichroic ratio of 2.94 at 808 nm. Our results provide a simple Bi based semiconductor system for high performance multifunctional optoelectronics and electronics compared with conventional Bi based chalcogenides.