Effect of Cu concentration on the structural and optical properties of hierarchically porous Cu-doped ZnO nanostructures

Abstract

Hierarchically porous Cu-doped ZnO nanostructures were formed on indium-tin-oxide (ITO)-coated glass substrates by using a template-free electrochemical deposition method. Field-emission scanning electron microscopy images showed that the density of the Cu-doped ZnO porous nanostructures increased with increasing Cu concentration. X-ray diffraction patterns showed that the lattice spacing of the (002) plane for the Cu-doped ZnO porous nanostructures decreased with increasing Cu concentration. Photoluminescence spectra for the Cu-doped ZnO porous nanostructures formed on the ITO-coated glass substrates showed that the dominant emission peak related to the band-to-band transitions shifted to a higher wavelength side with increasing Cu concentration.