Ultra-sensitive methanol detection based on S-vacancy-enriched SnS: A combined theoretical and experimental investigation

Abstract

Theoretical calculations have confirmed that modulation of vacancy defects could enhance the sensing properties of semiconductor gas sensors effectively. In this work, we develop a novel and cost-effective process to prepare S-vacancy-enriched SnS (Vs-SnS) for room temperature methanol sensors and further clarify the enhanced sensing mechanism of Vs-SnS based on first-principles calculation. The Vs-SnS were successful formed via one-step solvothermal process in Sn-rich environment, which could be confirmed by the results of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) techniques. Comparative investigations for methanol-sensing properties indicate that the Vs-SnS display an ∼143.9-fold enhancement in gas response at room temperature compared with conventional-SnS (C–SnS). Meanwhile, ultrafast response/recovery and low detection limit are observed for the Vs-SnS sensor (3 s of response time and 7 s of recovery time for 500 ppb methanol). The significant methanol sensing improvement could ascribed to the decrease in effective hole carrier concentration after introducing the S-vacancy as electron donor. The present study demonstrates the considerable effect and potential of vacancy modulation in the field of gas sensor applications, and the Vs-SnS is promising in highly sensitive methanol sensors with low consumption.