ZnO Nanowire Gate-Tunable Schottky Diodes by Adhesion Lithography

Electronic devices using nanomaterials have the potential to outperform equivalent devices using bulk materials, but only if nanoscale contacts can be made to the nanomaterial. This is achieved by a scalable process in this work through hydrothermal growth of horizontal ZnO nanowires (NWs) from a ZnO seed layer across a 40 nm nanogap created by adhesion lithography (A-lith). The asymmetric Ti and Au electrodes of the nanogap lead to the formation of Schottky diodes in the NWs, exhibiting rectification ratios >103. The addition of SiO2 dielectric around the NW improved the rectification ratio to almost 104 and allowed the addition of a bottom gate. The device demonstrated transistor-like behavior, most notably under reverse bias conditions. These characteristics are analogous to a source-gated transistor (SGT), with both accumulation and depletion modes of operation, demonstrating for the first time experimentally, SGTs with a size below 100 nm. This is significant as it opens up the possibility of nanoscale arrays of SGTs for ultra-high resolution displays or neuromorphic processors.