Synthesis, photoluminescence and ultrafast nonlinear optical properties of copper nanolayers/particles uniformly decorated ZnO nanowires

Abstract

Copper (Cu) nanolayers/particles decorated zinc oxide (Cu-ZnO) nanowires have been successfully synthesized by two-step chemical vapour deposition to prepare ZnO nanowires and magnetron sputtering method to deposit Cu nanolayers/particles. The field emission scanning electron microscopy images indicated the Cu nanolayers/particles are clearly visualized on surface of ZnO nanowires. The impact of sputtering time and sputtering power was analyzed. The results show that the atomic percent of Cu was gradually increased with the sputtering time and sputtering power was increased. The photoluminescence results demonstrated two major emission peaks for the Cu-ZnO nanowires, and the visible emission peaks of Cu-ZnO nanowires stronger than that of unmodified ZnO nanowires. Moreover, the results of open-aperture Z-scan measurements that all samples show the two-photon absorption behavior, and the two-photon absorption coefficients of Cu-ZnO is higher than that of unmodified ZnO nanowires. The results of closed-aperture Z-scan results demonstrated that all samples show self-focusing optical nonlinearity. These studies promise their potential applications in multifunctional optical devices.