Ethanol Sensing Performance of Au/TiO2/Ti TFT: Effects of Back Gate Biasing

Metal oxide semiconductor (MOS)-based gas sensors possess an excellent role for the detection of hazardous gases. In the present paper, synthesis, characterizations, and ethanol sensing performance of TiO2 nanosheet-based thin film transistor have been investigated. Synthesis of TiO2 was carried out by the low-temperature hydrothermal method at controlled pressure. The synthesized nanomaterial was deposited on RCA cleaned p-Si/SiO2 substrate. Structural (X-ray diffraction (XRD)) and morphological (field emission scanning electron microscopy (FESEM)) characterizations reveal crystalline size of ~ 9–11 nm with nanosheet-like structure. Electrical parameters of the resulting thin film transistor such as threshold voltage \((V_{{{\text{th}}}} )\) , effective field-effect mobility \((\mu_{{{\text{eff}}}} )\) , transconductance \((g_{m} )\) , , and subthreshold swing (SS) were found to be of 0.7 V, 96.26 cm2/V-s, 60.1 μS, 38 V/dec, respectively. Optimum sensor response upon exposure to ethanol was found to be 73% at room temperature (RT). Such room temperature ethanol sensing performance of Au/TiO2/Ti thin film transistor has been correlated with effect of back gate bias, surface trap states, and Wolkenstein adsorption–desorption isotherm.