Synthesis and optical properties of ultralong ZnO microbushes

Ultralong ZnO microbushes have been synthesized using a simple thermal evaporation and condensation method by Cu catalysts. The lengths of the ZnO microbushes range from several millimeters to more than one centimeter and the diameters of the branches' teeth are about 300 nm. The growth mechanism of the ultralong microbushes and the catalytic behavior of the copper are discussed. Room-temperature photoluminescence spectra of the ultralong ZnO microbushes showed a UV emission band at about 388 nm and wide green emissions at around 525 nm. It may be very attractive for commercial applications such as electrical devices, microelectromechanical systems and sensors.