Abstract
Transition metal dichalcogenides (TMDs) have received immense research interest in particular for their outstanding electrochemical and optoelectrical properties. Lately, chemical gas sensor applications of TMDs have been recognized as well owing to the low operating temperatures of devices, which is a great advantage over conventional metal oxide based sensors. In this work, we elaborate on the gas sensing properties of WS2 and MoS2 thin films made by simple and straightforward thermal sulfurization of sputter deposited metal films on silicon chips. The sensor response to H2, H2S, CO and NH3 analytes in air at 30 °C has been assessed and both MoS2 and WS2 were found to have an excellent selectivity to NH3 with a particularly high sensitivity of 0.10 ± 0.02 ppm−1 at sub-ppm concentrations in the case of WS2. The sensing behavior is explained on the bases of gas adsorption energies as well as carrier (hole) localization induced by the surface adsorbed moieties having reductive nature.
Highlights
Continuous and reliable detection of different gases is essential in industrial process monitoring, vehicle emission control, in and outdoor air quality safety and environment protection [1]
Chemical gas sensor applications of Transition metal dichalcogenides (TMDs) have been recognized as well owing to the low operating temperatures of devices, which is a great advantage over conventional metal oxide based sensors
Raman spectra of the films displayed in figures 1(e) and (f) indicate the materials are crystalline MoS2 and WS2, respectively [25, 26]
Summary
Continuous and reliable detection of different gases is essential in industrial process monitoring, vehicle emission control, in and outdoor air quality safety and environment protection [1] In these applications, traditionally metal oxide semiconductors such as SnO2, WO3, CeO2, Nb2O5 and ZnO. As well as their metal or metal oxide decorated derivatives have been most commonly utilized as sensing materials [2,3,4,5] While these sensors and their arrays offer excellent and reliable discrimination and even quantification of analytes, their operation is only possible at high temperatures that requires considerable power sourcing. With the spread of internet-of-things and dispersed networks that involve complex sensing systems with small but large number of devices, power consumption becomes a significant factor. New materials that would allow for low temperature operation could inevitably alleviate power related
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