Room temperature operated composite SnS–ZnS heterojunction based sensor for sub-ppm ethanol detection

Abstract The present work demonstrates the potential of metal sulphide SnS–ZnS composite towards detection of low concentration (sub ppm) ethanol at room temperature (27 °C). The fabricated sensor has shown excellent performance in terms of % response of 56.58% at 100 ppb owing to the low crystallite size observed from the x-ray diffraction (XRD) characterization. The sensor has been exposed to ethanol under relative humidity (RH) range of 40% RH to 80% RH. The sensor has shown fast response and appreciable selectivity towards ethanol. The elemental composition and valence states of the composite formed are shown using energy dispersive x-ray analysis and x-ray photoelectron spectroscopy. The excellent sensing behavior is also supposed to be contributed due to SnS–ZnS p-n heterojunction formation. XRD of the prepared sample has been done to find the crystal structure and crystallite size. Further, field emission scanning electron microscopy results have confirmed the low particle size of the sample which complements the high sensitivity of the sensor.