Synthesis of single-crystalline GeS nanoribbons for high sensitivity visible-light photodetectors

Abstract

Single-crystalline GeS nanoribbons were synthesized by chemical vapor deposition for the first time. Structural characterization revealed that the nanoribbons grow along the [01] direction with a thickness of 20–50 nm, a width of several micrometers and a length of hundreds of micrometers. The GeS nanoribbons show a p-type behavior verified from the field effect transport measurement. The nanoribbon photodetectors respond to the entire visible incident light with a response edge at around 750 nm consistent with the band gap absorption of GeS. A strong nonlinear light-intensity-dependent response was observed between the measured illumination intensity from 0.25 to 212 μW cm⁻². Under 530 nm light illumination, the maximum responsivity and external quantum efficiency are 139.9 A W⁻¹ and 32 730%, respectively. These results indicate that GeS nanoribbon is a promising semiconducting nanomaterial for high performance broadband visible-light sensing applications.