Optical properties of Co-doped ZnO nano powder material prepared by ball milling

摘要

Zn_(1-x)Co_xO nano powders have been successfully prepared by ball milling and have been annealing at 600°C. The crystal structure and optical properties of sample were characterized by X-ray diffraction (XRD), photoluminescence spectra (PL) and ultraviolet visible light absorption spectra (UV), and the formation mechanism was discussed. Co-doped ZnO nano powders exhibit wurtzite (hexagonal) structure. Co~(2+) enters into ZnO crystal structure and substitutes for Zn~(2+). All samples show typical luminescence behavior with about 396nm UV emission peak. In addition, the about 450nm and 470nm blue emission peaks are found in photoluminescence spectra. Before the doped content is within 8at%, the band edge of ultraviolet absorption appears red shift phenomenon with the increase of doping content. The peak position was shifted from 362nm (3.43eV) to 367nm (3.38eV). Annealing is in favor of the replacement that Co~(2+) enters into ZnO crystal structure and substitutes for Zn~(2+).