Highly sensible ZnO nanowire ultraviolet photodetectors based on mechanical Schottky contact

Highly sensible ultraviolet (UV) photodetectors were fabricated using vertically aligned dense ZnO nanowires based on mechanical Schottky contact with Pt coated polyimides. The effective mechanical contact was achieved by depositing transparent Al-doped ZnO (AZO) buffer layers prior to the growth of the nanowires, resulting in highly uniform nanowires with similar lengths. The AZO buffer and ZnO nanowires were prepared by atomic layer deposition (ALD) and metalorganic chemical vapor deposition, respectively. The electrical conductivity of the nanowires was varied by controlling the density of oxygen vacancies by using a controlled oxygen flow rate. The high conducting nanowire-based photodetector concurrently achieved a high photocurrent signal, fast response, and fast recovery, compared with high conducting film and low conducting nanowire photodetectors. A detailed discussion regarding the developed UV photo-detecting mechanism by the different conductivities and Schottky contact is presented in this work.