Multiple ZnO Nanowires Field-Effect Transistors

We report on the multiple ZnO nanowires field-effect transistors (FETs), which were formed by assembling as-synthesized ZnO nanowires on a SiO 2 /Si substrate using an optimized alternating current (AC) dielectrophoresis (DEP) technique in three-probe back-gate geometry. The AC DEP was optimized with a bias voltage of 10 V p-p at a frequency of 10 kHz. Our multiple ZnO nanowires FETs containing ca. 50∼65 nanowires in one device exhibited excellent electrical characteristics with a transconductance of 3∼11.5 μS at a drain voltage of 1∼5 V, a mobility of ∼30 cm 2 /V·s, and a carrier concentration of 9.4 × 10 17 cm -3 . For a comparison study, we also present conventional single ZnO nanowire FETs prepared by e-beam lithography with a back-gate structure.