Interface of a single ZnO-nanowire assembled onto custom-fabricated nanogap device for UV sensing applications

This work proposes a low-cost and easy-to-fabricate sensor based on single ZnO nanowire (ZnO-NW) assembled by dielectrophoresis (DEP) onto gold nanogap electrodes. Thanks to the widespread sensing properties of ZnO-NWs, the fabricated device can be used to monitor in real-time the UV-light. DC measurements have shown a Schottky-like I–V characteristic which varies depending on the UV light intensity. The AC analysis of the ZnO-NW electrical properties has also shown impedance variations proportional to the UV irradiance. In particular, the reported measurements show high sensitivity to low UV irradiance (below 1mW/cm²) translated to both resistive and capacitive variations. Thanks to the low-cost assembly process, the proposed nanowire-on-nanogap-based sensor can be considered a preliminary step to characterize nanomaterials before assembling them onto CMOS technology, opening the field to the Micro-for-Nano approach, i.e. an electronic circuit platform to integrate nanostructured materials and read-out their sensing parameters.