Enhanced Performance of ZnO Nanowire Field Effect Transistors by H₂ Annealing

Abstract

The electrical properties of ZnO nanowires are significantly dependent on their surface states. The surface trap charges degrade the device performance of field effect transistors. These trap charges are reduced by H2 annealing. In this work, a back-gate ZnO nanowire field effect transistor (FET) was fabricated by a photolithographic process, and its electrical properties were characterized. This back-gate FET was subsequently annealed under a flow of H2/Ar gas for 20 min. The back-gate FET annealed for 20 min exhibited remarkably enhanced electrical characteristics, as compared with the as-fabricated back-gate FET; the peak transconductance was increased from 40 to 448 nS, the field effect mobility from 27 to 302 cm2 V-1 s-1, and the Imax/Imin ratio from 1.5 to 105.