A fabrication technique for top-gate ZnO nanowire field-effect transistors by a photolithography process

In this study, top-gate ZnO nanowire field-effect transistors (FETs) were successfully fabricated using a photolithography process, and their electrical properties were characterized by I-V measurements. Their electrical characteristics were compared with those of back-gate ZnO nanowire FETs. The fabricated nanowire FETs exhibit good contact between the ZnO nanowire channels and Ti metal electrodes. A representative top-gate FET showed a higher gate dependence than a representative back-gate FET; the peak transconductances of the back- and top-gate FETs were 19 nS and 248 nS, respectively. These characteristics reveal that the top-gate nanowire FET fabricated by the photolithography process has better performance. The fabrication technique used for the nanowire FETs by a photolithography process in this study is applicable to the fabrication of various devices including TFTs, memory devices, photodetectors, and so on.