Hydrogen desorption effect on cathodoluminescence of ZnO

The effects of the low-energy electron beam on ZnO single crystals were investigated by cathodoluminescence (CL), Time-of-Flight Electron Stimulated Desorption (TOF-ESD) and Temperature Programmed Desorption (TPD). Under e-beam irradiation, the ultraviolet (UV) emission decreases exponentially for O-face, while it increases and then decreases for Zn-face. Meanwhile, a large desorption of H+ is observed by TOF-ESD for both O- and Zn-faces. On the other hand, an increase of H in the irradiated volume is observed after stopping the e-beam irradiation. Similar H2 desorption is found by TPD for both faces. These data suggest that the decrease of the UV intensity is related to H desorption.