Direct Integration of Metal Oxide Nanowire in Vertical Field-Effect Transistor

We demonstrate seamless direct integration of a semiconductor nanowire grown using a bottom-up approach to obtain a vertical field-effect transistor (VFET). We first synthesize single crystalline semiconductor indium oxide (In 2 O 3 ) nanowires projecting vertically and uniformly on a nonconducting optical sapphire substrate. Direct electrical contact to the nanowires is uniquely provided by a self-assembled underlying In 2 O 3 buffer layer formed in-situ during the nanowire growth. A controlled time-resolved growth study reveals dynamic simultaneous nucleation and epitaxial growth events, driven by two competitive growth mechanisms. Based on the nanowire-integrated platform, a depletion mode n -channel VFET with an In 2 O 3 nanowire constituting the active channel is fabricated. Our unique vertical device architecture could potentially lead to tera-level ultrahigh-density nanoscale electronic, and optoelectronic devices.