Dielectrophoretic assembly of GaN nanowires for UV sensor applications

Nanowire devices with back-gated structure were fabricated by dielectrophoresis-based assembly of GaN nanowires. GaN nanowires were aligned at the edge of the Ti/Au electrode patterns by applying electric fields. The results reveal that the assembly of the nanowires is affected by the electrode voltage and the size of the electrode patterns. Devices based on GaN nanowires suspended over the electrodes were fabricated and their electrical properties were investigated. The on/off ratio, electron carrier concentration, and electron mobility were ∼103∼103, ∼1018cm−3, and 52.1 cm2/V s, respectively. The nanowire devices suspended over the electrodes were applied to ultraviolet sensors, and a substantial increase of conductance under UV light with wavelengths of 365 and 254 nm was observed. Moreover, fast response and recovery time were observed.