Solvent sensors based on amorphous ZnSnO thin-film transistors

Abstract

Amorphous zinc–tin oxide (a-ZTO) thin-film transistors (TFTs) were prepared using a combustion solution method. The properties of the a-ZTO films and a-ZTO TFTs were studied in detail. For applications, a-ZTO TFTs are used as solvent sensors. The a-ZTO TFTs exhibited strong sensitivity and selectivity in detecting solvents (e.g., cyclohexane, ethanol, and deionized water). The electron donors in the ZTO channels were determinated by the polarity of the solvent, which affects the location of the Femi level (E_f). Moreover, a feasible mechanism model related to the electron transfer channel (ETC) was proposed to explain the sensor behaviours. This model can be applied to most of the amorphous oxide TFT sensors. This work is expected to not only provide an insight into the fundamental understanding of the behaviours of amorphous oxide TFT biosensors, but also to offer a basic design guideline for device fabrication in this system.