Green Cathodoluminescence Properties of Zinc Oxide Films Prepared by Excimer Laser Irradiation of a Sol–Gel-Derived Precursor

Green cathodoluminescent (CL) ZnO films were prepared at a low substrate temperature (473 K) in air by KrF-excimer laser irradiation of a sol-gel-derived precursor (ELISG method). Structures and CL properties of the films irradiated by the laser at different energy fluences (Ef) were studied and compared with those of a film prepared by conventional heat treatment in a reducing atmosphere. The prepared ZnO films showed a green CL band peaking at around 510 nm, in addition to an ultraviolet CL band. The maximum intensity of the green CL was obtained from a film produced by laser irradiation at an Ef of 130 mJ/cm2. Near-IR spectroscopy suggested that the green CL intensity depends on free-carrier concentration of the films and is maximized at an appropriate concentration. The formation process of the green CL films by the ELISG method was discussed in terms of thermal and photoinduced effects induced by the laser irradiation. 23 refs.