The Origin of Green Emission of ZnO Microcrystallites: Surface-Dependent Light Emission Studied by Cathodoluminescence

Green emission of ZnO microcrystallites has been studied in detail by directly investigating the luminescence from the different crystal surfaces of ZnO microcrystallites by means of room temperature cathodoluminescence (CL). The relative strength of the green emission was found to be strongly dependent on the crystal surfaces. By discussing the atom structures of different crystal surfaces, it is concluded that the green emission mostly comes from the defects on/near the surfaces.