Highly Efficient Room Temperature DMA and TMA Sensor Based on MoS2–ZnO Hybrid Channel FET Device

Abstract

In this letter, a back-gated field effect transistor (FET) sensor with MoS₂–ZnO hybrid channel is reported for efficient detection of dimethylamine (DMA) and trimethylamine (TMA) vapors, the two primary amines that are primary bio-indicators for many applications, such as quality monitoring of freshness of fish, biomarker for couple of diseases, such as nonalcoholic fatty liver disease (NAFLD), renal disorder, etc. Compared to the state of the art, the developed sensor offered three distinct advantages: i) this is the first report of DMA, TMA detection with FET device employing MoS₂–ZnO hybrid channel offering fast response and recovery; ii) the ability to detect the target species at room temperature owing to very high free surface energy associated with the hybrid channel region; iii) improved lowest detection level (0.5 ppm for DMA and 1 ppm for TMA) due to excessively high surface to volume ratio. The underlying mechanistic framework for such superior performance was primarily attributed to the judicious choice of the channel material coupled with device architecture. Formation of the p-n junction (p-MoS₂ and n-ZnO) in the channel region and the associated charge separation assisted field generation therein leads to easy dissociation of target vapor species (low operating temperature and improved lowest detection level), while the majority carrier-driven fast charge transport in the channel region causes fast response and recovery in such FET device.