Laser action in ZnO nanoneedles selectively grown on silicon and plastic substrates

An ion-beam technique has been employed to fabricate nanoscale needlelike structures in ZnO thin films on silicon and plastic substrates at room temperature. The ZnO nanoneedles showed a single-crystalline wurtzite structure, the stem of which was around 100 nm in diameter. The sharp tips of the nanoneedles exhibited an apex angle of 20 degrees as measured by transmission electron microscopy. Room-temperature ultraviolet random lasing action was observed in the ZnO nanoneedle arrays under 355 nm optical excitation. (c) 2005 American Institute of Physics.