SUPERLINEAR INCREASE PHENOMENON OF UV LUMINESCENCE OF ZnO FILM UNDER CATHODOLUMINESCENT EXCITATION
Guo Changxin Fu Zhuxi Shi Chaoshu (Department of Physics, University of Science and Technology of China, Hefei 230026)
The dependence of ultraviolet (～390nm) and green (～520nm) luminescent peaks of ZnO film prepared by direct curren sputtering under cathode ray excitation on excitation electron beam current has been investigated. With the increase of the intensity of excitation electron beam current, green peak relatively decreases and ultraviolet peak relatively increases, so that the luminescent color or ZnO film changes from green to blue violet. The green peak intensity increases sublinearly with the increase of the intensity of electron beam current and saturates under relatively low intensity of electron beam current. But the 390nm ultraviolet peak intensity increases superlinearly with the increase of the intensity of electron beam current. This is a sign of emitting ultraviolet laser from ZnO film under cathode ray excitation under room temperature. This kind of ultraviolet laser from ZnO film may come from a super radiation lasing luminescence under high density excitation.