Unusual enhanced photoluminescence from highly lattice mismatched ZnO/Cu3N multilayer films

ZnO/Cu3N multilayer films with different oxygen partial pressures are deposited by radio frequency magnetron sputtering method. The crystal structures and optical properties are analyzed by using X-ray diffraction (XRD) patterns, reflectance spectra, absorbance spectra and PL spectra. Both Cu3N (111) and ZnO (002) diffraction phases are observed in the XRD patterns of all the ZnO/Cu3N multilayer films. In addition, XRD results also indicate that the lattice mismatch f(m) is 38.28% for ZnO/Cu3N multilayer film with 5:25 sccm and reaches the maximum value among all samples. Generally, highly lattice mismatched multilayer films always undergo serious residual strain, which cause PL quenching. However, in this work, the intensity of three emission peaks ranging from violet to blue-green wavelength in ZnO/Cu3N multilayer films attain to strongest at a low oxygen partial pressure of 5:25 sccm. Based on experimental results, we propose unusual enhanced photoluminescence (PL) mechanism from highly lattice mismatched ZnO/Cu3N multilayer films. (C) 2016 Elsevier Ltd. All rights reserved.