Effects of Au layer thickness and number of bilayers on the properties of Au/ZnO multilayers

Multilayered films of Au/ZnO were prepared by physical vapor deposition. Varying the Au thickness, t(Au), and the number of bilayers, n, allowed us to investigate the role of these parameters on the sample structural and electronic properties. X-ray diffraction, X-ray absorption spectroscopy, grazing incidence small angle X-ray scattering and transmission electron microscopy experiments, have been combined to UV-visible and infrared spectroscopy to characterize the multilayers in the as-prepared state and after annealing. In the as-prepared state, the strong Au and ZnO lattice interaction leads to ZnO epitaxy on Au. Gold appears either as continuous layers or in form of nanoparticles. ZnO experiences a structural transformation from wurztite to rock salt monitored by the Au morphology. Annealing at 500 degrees C destroys the lattice matching. The electronic and optical properties of the systems are understood in line with the Au morphology and ZnO structural state. (C) 2011 American Institute of Physics. [doi:10.1063/1.3580333]