Photoluminescence study of ZnO nanostructures grown on silicon by MOCVD

► The size and shape of ZnO nanostructures depend on growth temperature. ► The size reduction of ZnO nanostructures causes a UV shift of the edge-band PL line. ► A higher growth temperature can decrease the number of deep level defects. ► Hydrogen appears to be an impurity donor in the ZnO nanostructures. ► The PL line at 373.7 nm can be attributed to oxygen vacancies.