Selectivity of MoS2 gas sensors based on a time constant spectrum method

In this report, MoS2 field-effect transistor gas sensors were fabricated and demonstrated to selectively sense and distinguish different gas species. The sensing behaviors of three individual gas species including O2, water vapor, and ethanol were first characterized. The transient drain current responses after the gate voltage induced gas adsorption/desorption were then recorded and decomposed into multiple exponential terms with different time constants, which are indicators of specific gas species adsorbed on MoS2 surface. Using this time constant spectrum method, selective sensing among O2, water vapor and ethanol was demonstrated. It provides a simple and practical approach for MoS2 field-effect transistor gas sensors to selectively sense various gas species.