Effect of hydrogenation on the cathodoluminescence properties of ZnO single crystals

The effect of hydrogenation on the intensity evolution of ZnO single crystal under electron beam irradiation was investigated by cathodoluminescence (CL). Without hydrogenation, the ultraviolet (UV) emission for O-face decreases exponentially and reaches a constant value with e-beam irradiation, while that for Zn-face once increases and then decreases. The hydrogenation significantly increases the UV emission for both faces. On the other hand, the amplitude of the decreasing component of the O-face becomes larger, while the increasing component is not affected. These results suggest that hydrogen only affects the decreasing component of the UV intensity evolution.