Fabrication of Ag embedded−SnS films via the RF approach: First study on NO2 gas–sensing performance

Abstract

We report on the synthesis of 5-nm thick-Ag embedded−SnS (Ag/SnS) films by the radio frequency (RF) sputtering method as an absorbent layer to detect NO2 gas. Structure, morphology, elements, and optical properties of the Ag/SnS films were studied by X − ray diffraction, scanning electron microscopy, energy−dispersive spectroscopy, Raman and photoluminescence techniques, respectively. We firstly investigated the sensitivity of 5 – 20 ppm concentration of the Ag/SnS films to NO2 gas at an operating temperature ranging 30 – 100 °C. It was indicated that the Ag/SnS film–based sensor got good response and recovery at an operating temperature of 80 °C for NO2 gas. The 100 nm thick SnS film−based sensor made a faster response time (40 s) and recovery time (1320 s) to 20 ppm NO2 gas at 30 °C than those of other SnS films−based sensors. The result shows that the Ag/SnS film might be suitable for improving NO2 sensor properties due to the enhanced hole mobility, and more defectiveness of the SnS monolayer (Sn–vacancy). Based on these findings, we propose the fabrication of nanometals on SnS film for the high sensitive and selective NO2 gas−sensing a lower detection limit and at room temperature.