Abstract: The wide bandgap III-V nitride and ZnSe based II-VI semiconductor materials are the focus of intense world-wide research due to the recent development of blue-green light emitting diodes （LEDs） and blue laser diodes （LDs）. An important factor in these advances has been the continuous improvement in materials quality as well as the introduction of innovative approaches to doping. Zinc oxide （ZnO） is a wide and direct bandgap II-VI semiconductor, which has some promising properties including, in particular, a high exciton binding energy of 60meV, and is another material which may yet find uses in commercial photonic devices. In this paper the plasma enhanced molecular beam epitaxy of ZnO single crystal thin film are described, and the emphasis is placed on the optically pumped lasing from ZnO and its excitonic stimulated emission mechanisms above room temperature. The possible ZnO-based photonic application is discussed in the light of recent experimental findings.