Tuning the Threshold Voltage of a SnO2 Nanowire Transistor Through Microwave-assisted Metal-oxide Reduction

Abstract

Numerous studies have suggested that n-type semiconductor nanowires provide excellent electrical properties, as well as notable mechanical flexibility, to electronic devices. However, the dynamic threshold voltages of these devices significantly reduce our ability to produce robust and stable transistors consistently. In this study, tuning of the threshold voltage (Vth) of a SnO2 nanowire transistor was investigated by using a household microwave oven to control the oxygen vacancies on the surface of the SnO2 nanowire. The extent of the negative shift in the Vth of the SnO2 nanowire transistor was controlled by varying the applied power and time of the microwave irradiation in the atomic weight percentage of oxygen on the SnO2 nanowire’s surface. A Vth shift of −0.42 ± 0.69 to −4.25 ± 0.52 V was observed when the applied power was varied from 200 to 1000 W while a shift of −0.46 ± 0.27 to −9.87 ± 0.67 V occurred for microwave irradiation times of 20 to 80 s. Thus, the Vth could be tuned over a wide range by controlling the irradiation time while it could be fine-tuned using the applied power. The Vth characteristics of the controlled SnO2 nanowire transistors were monitored over 20 days in a normal atmosphere and were observed to remain unchanged. Notably, these characteristics were achieved without the application of an additional passivation layer. This method, which is simpler and more effective than other existing methods, can be readily applied for the production of SnO2 nanowire transistors.