ZnO

as a wide direct bandgap and large exciton binding energy semiconductor material

has stimulated great interests because of its promising application in ultraviolet optoelectronic devices

ultraviolet light-emitting diodes and ultraviolet laser diodes.Nanostructural ZnO is beneficial to increase the exciton recombination probability and to lower the pumping power threshold due to the high state density near the band edge.The research progress on ultraviolet spontaneous emission and stimulated emission of nanostructure ZnO is(reviewed) mainly based on some novel morphologies which were fabricated in our experiments by vapor phase transport(VPT) processes.For a ZnO nanostructure with good crystal quality

the photoluminescence presents a strong ultraviolet band emission originated from the band-edge excitonic recombination.The perfect crystalline nanostructure with strong UV spontaneous emission is required for ZnO nanolaser.In our experiments

the ultraviolet amplified spontaneous emission(ASE) has been observed in ZnO nanofiber network(arrays) with 6-symmetry structure fabricated on a catalyst-patterned substrate.The UV light was gained in the network arrays and amplified gradually duo to the nature wave guide properties of the ZnO nanofiber branches.When the pumping power is high enough

ASE happened.The UV laser of ZnO have been obtained in three type of resonant cavities

random cavity

Fabry-Perot cavity and whispering gallery mode(WGM) cavity.In our research

ZnO microtubes have been employed as F-P cavity and a UV stimulated emission signal has been obtained and analyzed

which is similar to the phenomena in nanorods

nanobelts and nanocombs reported by other researchers.It is noted that a novel structure of ZnO

single crystal nanodisk has been fabricated in our experiments.It is expected to be as WGM cavity with low loss

low threshold and high quality factor.