This thesis describes the growth and characterisation of ZnO thin films and nanostructures grown using the pulsed laser deposition technique. In this technique, a solid state Nd:YAG laser operating at 266 nm and with a 6 ns pulse width was fired at a sintered, ceramic target to produce an expanding plume of ZnO into a vacuum chamber (pressures in the 10−1 mbar range). The plume material condenses on various substrates, chiefly sapphire, to form a thin film. The samples were analysed using a range of structural, optical, and surface analyses to determine the effects that varying pressures, temperatures, and laser energy fluence had on the growth modes of these thin films and nanostructures. Additionally, a study was carried out to determine the effects a mixed background gas (O2 and Ar) has on the nanostructured growth. A model for this case was proposed. Finally, a biomedical application of ZnO was investigated to determine the potential of ZnO thin films for the sterilisation of biofilms of the bacterium Staphylococcus epidermidis. It was found that such a biofilm grown atop a ZnO thin film is inactivated after exposure to UV light while submerged in an aqueous solution.