Simple Fabrication Method for Solution-gated One-piece Transistors for Biosensing Applications

In this paper, we report on a novel and simple fabrication method for solution-gated thin-film indium tin oxide (ITO) channel field-effect transistors (FETs). These devices can be fabricated by etching a part of deposited conductive ITO film with about 100 nm thickness to 20 nm thickness as the channel, which exhibits semiconductor characteristics. The current measurement during etching enables the direct observation of the change in current at the channel, that is, the precise optimization of FET characteristics. The devices fabricated show a steep subthreshold slope (~80 mV/decade) and a large I d / I g ratio; thus, they have the potential to be applied in highly sensitive affordable biosensors.