A simple band model for ultraviolet induced ambipolarity in single SnO2 nanowire devices

Abstract

Single Tin Dioxide nanowire (SnO 2 NW) field-effect-transistors (FET) devices have been a great candidate to build electronic circuits, as chemical and physical sensors and study low dimensional properties and related effects. Ambipolarity is one of those effects that may direct its use for specific purposes, where a controllable separated unipolar mode can be achieved in one single device. SnO 2 NWs grown by the VLS method were used for single NW devices fabrication by direct photolithography using the simple back-gate FET architecture. Single SnO 2 NWFET's transport properties were explored, where on/off ratio, mobility and carrier density parameters were extracted, resulting in values around 10 5 , lower than 0.1 cm 2 /V and in the order of 10 19 /cm 3 , respectively. When under ultraviolet (UV) light, all devices presented UV induced ambipolary effect, where on/off states ratio with values of the same order were obtained and ranged from 1.12 to about 19.34. A simple band model was then proposed to explain such behavior. • Ambipolarity allows a controllable separated unipolar mode in FET devices. • Back-gated single n-type SnO2 NWFET showed light induced ambipolarity conduction. • Simple band diagram model fully explains the ambipolarity behavior.