Cathodoluminescence Quenching in Yb-Doped ZnO Nanostructures

Cathodoluminescence (CL) quenching was observed in ZnO nanostructures when doped with Yb by both chemical and physical methods. CL spectra of the samples revealed a defect emission at 2.25 eV in samples prepared by the chemical method, and an emission at 2.5 eV in samples prepared by the physical method. From the thermal treatment studies, it was found that oxygen vacancies are responsible for the 2.5 eV emission. Observed CL quenching in ZnO is explained through the participation of point defects in the energy transfer process from ZnO to Yb3+.