Gallium phosphide (GaP) nanowire transistors were fabricated in back-gated structure, and their electrical characteristics were measured systematically in both air and vacuum. The transistors turn on typically between -5 and -7 V in ambient air. However, a large threshold voltage (Vth) shift, ∼10 V, toward negative gate bias was observed in vacuum. After the transistors were exposed to air for 48 h, Vth returned to the similar value in ambient air, implying a reversible process. The rate of Vth shift slows down when they were exposed to N2 in comparison with that of air. The shift of Vth is believed to be related to the charge transfer from the surface of GaP nanowire to the physically adsorbed OH or oxygen. In addition, the observed Vth shift from the GaP nanowire transistors can be explained by the conventional n-channel depletion mode metal-oxide-semiconductor field-effect transistor.
ASJC Scopus subject areas
- Physics and Astronomy(all)