Temperature dependence of current and low-frequency noise in InAs nanowire transistors

Semiconductor nanowires are typically fabricated into transistors using metal source and drain contacts but no doping profile, leading to devices that operate as Schottky-barrier field effect transistors rather than traditional MOSFETs. Because of this fundamental difference in geometry, the devices will operate with greater influence from the contacts in both current and noise behavior, yet many previous studies still apply traditional MOSFET models to nanowire devices. By studying the mechanisms of contact and channel effects in nanowire transistors, the devices can be better understood in terms of fundamental limits of performance and scaling. In this study, variable temperature measurements were used to investigate the contact properties in relation to current and noise and understand physical models of device operation. 30 nm diameter InAs nanowires were grown by the VLS method and formed into back-gated transistors. Nickel source and drain contacts form channel lengths of 500 nm. The wires sit on silicon wafers with 100 nm oxide which acts as a back gate.