Photoluminescence properties of Co-doped ZnO nanorods array fabricated by the solution method

Highly ordered pure and Co-doped ZnO nanorod arrays were synthesized by a solution method at low temperature. The structures and morphology of the samples were studied by XRD, EDS and FESEM as well as Raman, which reveal that the samples are wurtzite structure; the Co atoms successfully substitute Zn atoms positions in nanocrystal. The PL properties of the as-prepared specimens were principally investigated using PL spectroscopy at room temperature and ultralow temperatures. The results strongly disclose that Co-doping can effectively adjust the energy level and abound the contents of surface states in ZnO nanorods, which lead to shift in the emission peak position in ultraviolet (UV) region and enhance the luminescence performance in visible (VL) light region of nanorod arrays. In addition, the slow vibration of phonons in nanocrystal lattice at ultralow temperature can also possibly contribute towards the novel emission performances of Co-doped arrays.