Photoluminescence and highly selective photoresponse of ZnO nanorod arrays

Abstract Well-aligned ZnO nanorod arrays were grown on the Si substrate via a hydrothermal method. Room-temperature photoluminescence (PL) measurements of the nanorods show that after annealing in air, the green emission enhances whereas the ultraviolet (UV) emission quenches along with the near-infrared emission. The mechanisms for the changes of emissions in the PL spectra were discussed and investigated. A new and simple method was created to fabricate the metal–semiconductor–metal (MSM) photodetectors based on ZnO nanorod arrays. The current–voltage ( I – V ) curve of the device shows double Schottky diode characteristics in the dark, and it transforms to Ohmic under UV illumination. The photogenerated current under 365-nm UV illumination is almost 25 times higher than that under 254-nm UV illumination, which is due to the easier recombination of electron–hole pairs under 254-nm UV irradiation.