Temperature-dependent shifts of near band-edge emission and their second-order diffraction for ZnO nanorods

Abstract The crystal structure and morphology of ZnO, grown on silicon substrate by two-step method, were measured by X-ray diffraction and field emission scanning electron microscopy. The results reveal that the sample is mainly composed of ZnO nanorods and preferentially oriented in the c -axis direction. The photoluminescence properties of the ZnO nanorods were investigated over the temperatures from 10 K to 297 K. There exist three emission bands in near band-edge, green–yellow–orange–red and near-infrared, respectively. Donor bound exciton (D 0 X) and its phonon replicas emission peaks were observed in low temperature photoluminescence (PL). The D 0 X and its phonon replicas peak intensity decreased with the increase of temperature and disappeared when the temperature increased up to 87 K. The decay in the D 0 X and its phonon replicas emission peak intensity stemmed from the thermal dissociation of D 0 X to free exciton. Temperature-dependent second-order diffraction of the near band-edge emissions were investigated in detail.