ZnO thin films grown on platinum (111) buffer layers by pulsed laser deposition

C-axis oriented ZnO layers were grown by pulsed-laser deposition on the surface of a platinum (111) epitaxial thin film supported by a c-sapphire substrate. The Pt bottom layer provides good in-plane lattice matching with c-ZnO, enabling epitaxial re-growth of the latter, as shown by X-ray diffraction data. Room- and low-temperature reflectance and photoluminescence measurements have been performed on such ZnO/Pt heterostructures for the first time. Intense resonances, corresponding to the A and B free excitons, are clearly evidenced in the reflectance measurements at 30 K, while the deconvolved full widths at half maximum of the bound excitonic lines, observed in the photoluminescence spectra at 28 K, range between 3 and 7 meV. This report clearly demonstrates that ZnO epitaxial thin films with very good structural and optical properties can be grown on a Pt bottom electrode and, thus, establishes the potential of this material system for use in ZnO-based optoelectronic devices.