Thermal annealing effects of MBE-seed-layers on properties of ZnO nanorods grown by hydrothermal method

ZnO nanorods on seed-layers were grown by the hydrothermal method. The seed-layers were grown by plasma-assisted molecular beam epitaxy (PA-MBE) and then in-situ annealed in O2 plasma at the temperatures of 500, 700, and 800 °C, respectively. The effects of annealing temperature of the MBE-seed-layer on properties of the ZnO nanorods were investigated by using atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and photoluminescence (PL). By the increase in the annealing temperature, the grains coalesce and their size becomes larger. The densities of the ZnO nanorods grown on the annealed MBE-seed-layers are higher than that of the as-prepared ZnO nanorod and their average grain size is gradually decreased. The optical properties such as the PL intensity ratio of the NBE to DLE and FWHM of the ZnO nanorods grown on the annealed MBE-seed-layers is enhanced compared with that of the as-prepared ZnO nanorod.