Visible Photoluminescence of Ultrathin ZnO Nanowire at Room Temperature

Zinc oxide (ZnO) nanowire (NW) was grown on a ZnO-buffered silicon substrate by a hydrothermal method in an aqueous solution that contained methenamine (C 6 H 12 N 4 ) and zinc nitrate hexahydrate (Zn(NO 3 ) 2 ·6H 2 O). The concentration of the zinc nitrate is the main factor that governed the morphology of the NW. As the concentration was reduced gradually, the diameter of the NW became smaller, and an ultrathin (≤10 nm) single crystal of ZnO NW emerged. The sample of ultrathin NW contains many dislocations and exhibits an unusual characteristic photoluminescence (PL) spectrum in the visible light region.