Control of ZnO nano-crystals synthesized by nanoparticle-assisted pulsed laser deposition using buffer layer and laser irradiation

Various ZnO nanocrystals, such as nanowires, nanorods, and nanowalls, have been successfully synthesized by a nanoparticle-assisted pulsed laser deposition (NAPLD). In this study, we have succeeded in controlling the growth density and position of the ZnO nano crystals with a ZnO buffer layer and a buffer layer patterned by interference laser irradiation, respectively. Vertically aligned ZnO nanowires with low lateral density were grown on the ZnO buffer layer, and each nanowire was grown at the tip of the hexagonal cone-shape ZnO core formed on the layer. The lateral density of the ZnO nanowires can be controlled by the buffer layer thickness. In addition, laser irradiation to the buffer layer can also control the density, because the density of the nanowire grown on the laser-irradiated layer was clearly decreased as compared with no-irradiated layer. Furthermore, patterned growth of ZnO nano crystals was demonstrated using four beam interference patterning. The buffer layer and interference laser irradiation can be used as one of the effective additives to control the growth of the ZnO nano crystals synthesized by NAPLD.