Characteristics of ZnO nano-crystals grown on Al-doped ZnO thin films deposited by using the PLD method

ZnO nano-crystal thin films were fabricated on Al-doped ZnO/SiO2/Si substrates prepared by using pulsed laser deposition with a solvothermal technique at a low temperature. The Al-doped ZnO substrate and ZnO nano-crystal thin films were preferably oriented in the (00l) direction. In films, nucleation can be facilitated by the presence of the substrate, which constitutes a site for heterogeneous nucleation. ZnO nanorods were grown on Al-doped ZnO substrates in lengths of 178.8, 851.4, and 916.2 nm for growing time of 24, 48, and 96 h, respectively. The ZnO nanorod thin film arrays with diameters of 45 ∼ 100 nm were separated by gaps of 30 ∼ 90 nm. Photoluminescence (PL) spectroscopy using a He-Cd laser (325 nm, 40 mW) was employed to characterize the ZnO nanorod thin films. A strong blue emission centered at 377 nm was clearly observed at room temperature.