Depth profile of ZnAl2 O4 layer on sapphire substrate by cathodoluminescence

ZnAl
₂
O
₄
thin film for ultraviolet emitting phosphor prepared by deposition of ZnO on c-sapphire substrate and thermal diffusion process. The deflections of Zn and Al atoms in the films were confirmed by cathodo-luminescence properties. The CL intensity of ZnAl
₂
O
₄
was not saturated from the film annealed for 100 hours, however, the saturation of UV emission was observed under anode voltage of 8 kV in the film annealed for 200 hours. It is thought that the thickness of ZnAl
₂
O
₄
film became thinner by longer annealing at high temperature because of Zn re-evaporation. From cross-sectional FE-SEM observation, it was confirmed that the correct thickness and atomic distributions in the film. Since the ZnAl
₂
O
₄
film thickness of the sample annealed for 100 hours was about 1μm by FE-SEM, it was suitable the penetration depth of the electron into ZnAl
₂
O
₄
layer.