Properties of Suspended ZnO Nanowire Field-Effect Transistor

Abstract

As a II-VI compound semiconductor with a wide and direct band gap of 3.37 eV, ZnO nanowires have attracted intensive research effort due to their unique properties and potential application as transistors, light-emitting diodes, photodetectors, and chemical sensors. Studies of the electrical transport characteristics, as well as the optical properties and mechanical properties of individual ZnO nanowires have been reported recently. In this report, the characteristics of suspended nanowires are presented. Single-crystalline ZnO nanowires are synthesized by a vapor trapping chemical vapor deposition method. They are configured as field-effect transistors (FET) with a suspended ZnO nanowire channel. Contacts between the ZnO nanowire and metal electrodes are improved through annealing and metal deposition using a focused ion beam. The gas sensing characteristics are studied and compared to those of the nonsuspended structure. In addition, the surface potential distribution of the suspended nanowire is investigated using scanning probe microscopy to characterize the uniformity of the nanowire. Continued work is underway to reveal the intrinsic properties of suspended ZnO nanowires and to explore their device applications.