Vertically oriented nanowires(NWs)of single-crystalline wurtzite GaN have been fabricated on a-LiAlO_(2)(100)substrate coated with a Au layer,via a chemical vapor deposition process at 1000℃ using gallium and ammonia as source materials.The GaN NWs grow along the nonpolar[10]direction with steeply tapering tips,and have triangular cross-sections with widths of 50100 nm and lengths of up to several microns.The GaN NWs are formed by a vapor liquid solid growth mechanism and the tapering tips are attributed to the temperature decrease in the final stage of the synthesis process.The aligned GaN NWs show blue-yellow emission originating from defect levels,residual impurities or surface states of the GaN NWs,and have potential applications in nanotechnology.
