In this work a simple method to produce the ZnO nanosheets (NSs) with inclusions of Cu nanocrystals by means of electrochemical etching without the necessity of any surfactant has been presented. The Raman spectroscopy demonstrates that the amorphous samples of ZnO-Cu present appreciable changes in its vibrational behavior after the thermal treatment at 400°C in ambient atmosphere. The study of Photoluminescence (PL) shows monotonous increasing the bands centered in 3.07, 2.41, 2.03 and 1.57 eV versus etching time in freshly prepared samples. The intensity variation of the PL bands, the changes in vibrational behavior, as well as the impact of the copper content and preparation conditions allow identifying emission inside the visible spectral range related to the surface defects that is interesting for the future possible application this ZnO system in room temperature “white” light-emitting diodes.

Photoluminescence (PL), scanning electronic microscopy (SEM) and Raman scattering have been studied in crystalline ZnO nanosheets with different sizes after the thermal annealing at 400 °C for 2 hours in ambient air. ZnO nanosheets were created by the electrochemical (anodization) method using the variation of the etching durations with obtained ZnO nanosheet sizes from the range 40-360 nm. Earlier it was shown using the X ray diffraction (XRD) method that thermal annealing performed the ZnO oxidation and crystallization with the creation of the wurtzite crystal lattice. Four PL bands are revealed in PL spectra with the PL peaks at 1.60, 2.08, 2.50 and 3.10 eV. Size decreasing of ZnO nanosheets stimulates tremendous changes of ZnO optical parameters. It is shown that decreasing the ZnO nanosheet sizes is accompanied by the intensity increase of a set of Raman peaks and the surface defect related PL bands. The reasons of emission transformation and the nature of optical transitions have been discussed as well.