Papers by Author: Mitsuhiro Okamoto

Abstract: In order to clarify the fundamental luminescent mechanism of undoped and Er-doped ZnO thin films synthesized by sputtering method, cathodoluminescence (CL) from the samples formed on several kinds of substrate were measured. There was no explicit peak identified with luminescence from ZnO crystal defects in undoped sample, on the contrary, three sharp luminescent peaks were observed in the case of Er-doped ZnO film due to the internal transition of the additive Er ions in the CL spectrum. The mechanism was investigated in comparison with photoluminescence (PL).

Abstract: Er-doped ZnO thin films which emitted intense infrared light in the vicinity of 1.5 μm were investigated from points of view of the microstructure and electrical properties. The result of X-ray diffraction (XRD) pattern revealed that the crystal lattice of ZnO was apparently expanded by doping of Er ions. Electrical resistance in the direction of thickness of Er-doped ZnO film showed linear behavior, which was resemble to that of undoped ZnO film. Infrared light emission phenomenon of the film was related to the chemical / physical state of Er ions in ZnO matrix.