High-Mobility Solution-Processed Tin Oxide Thin-Film Transistors with High-κ Alumina Dielectric Working in Enhancement Mode

Solution-processed metal oxide thin-film transistors (TFTs) operating in enhancement mode are promising for the next-generation flat panel displays. In this work, we report high-mobility TFTs based on SnO2 active layer derived from a soluble tin(II) 2-ethylhexanoate precursor. Densely packed polycrystalline SnO2 thin films with moderate oxygen vacancies and only a few hydroxides are obtained via systemically optimizing precursor concentrations and processing conditions. The utilization of a solution-processed high-kappa Al2O3 insulating layer could generate a coherent dielectric/semiconductor interface, hence further improving the device performance. TFT devices with an average field-effect mobility of 96.4 cm(2) V-1 s(-1), a current on/off ratio of 2.2 x10 (6), a threshold voltage of 1.72 V, and a subthreshold swing of 0.26 V dec(-1) have been achieved, and the driving capability is demonstrated by implementing a single SnO2 TFT device to tune the brightness of an organic light-emitting diode. It is worth noting that these TFTs work in enhancement mode at low voltages less than 4 V, which sheds light on their potential application to the next-generation low-cost active matrix flat panel displays.