Properties of zinc oxide thin films prepared on silicon (100) and glass substrates by pulsed laser deposition technique with different oxygen gas pressures

Abstract

Nanostructured zinc oxide (ZnO) thin films were prepared on silicon (100) and Corning glass substrates by pulsed laser deposition (PLD) technique with different oxygen gas pressures. The microstructure, crystallinity and resistivity of the ZnO films are found to be dependant on the oxygen gas pressure. The X-ray diffraction (XRD) analysis showed that the growth of grains occurred along the c-axis of ZnO films obtained under high oxygen gas pressures. The ZnO films were oriented preferentially along the (002) direction, which is responsible for good electrical and optical properties. Pulsed laser deposited ZnO films, with the c-axis orientation (except for the ZnO films grown at room temperatures), show low structural defects. By applying higher oxygen gas pressures, the grain size of the films is found to increase, the electrical resistivity tends to decrease and the optical transmittance in the visible region becomes higher. The surface morphology of the films measured by scanning electron microscopy (SEM) showed nanostructures with surface which is smooth and without any cracks.