Strong violet emission from zinc oxide dumbbell-like microrods and nanowires

ZnO of different morphologies with controlled size and aspect ratio (l/d) such as dumbbell-like microrods, thick nanowires and thin nanowires were prepared by a hydrothermal method. Possible mechanisms for the formation of ZnO crystals with the different morphologies were discussed. Strong violet photoluminescence bands at∼413 nm (3.0 eV) without band edge emission were observed from the dumbbell-like ZnO microrods and thick nanowires. Correspondingly, the thin nanowires showed a weak shoulder UV photoluminescence band at∼390 nm. Such result indicates that the photoluminescence properties could be improved by the morphologies or aspect ratio (l/d) and the potential fabrication violet-light-emitting devices.