Naoto Koshizaki

SYNTHESIS AND CHARACTERIZATION OF Au/ZnO NANOCOMPOSITES

Au/ZnO nanocomposite thin films were prepared by co-sputtering of ZnO and gold. The Au content in the films was varied by varying the length of gold wires on the ZnO target. Depending upon the Au content in the films, the Au nanoparticles of different average size values were formed in the ZnO matrix. The composite films were annealed at different temperatures to study the evolution of Au particles and the subsequent change in their optical properties. With the increase of Au content in the films, the size of the nanometric Au particles decreased but increased with the increase of annealing temperature.

NANOSTRUCTURE AND PHOTOLUMINESCENCE PROPERTY OF Si/MgO AND Si/ZnO CO-SPUTTERED FILMS

Abstract Si MgO and Si ZnO films were deposited by placing Si plates on an MgO or ZnO target during sputter deposition. X-ray photoelectron spectroscopic (XPS) analysis revealed that the average Si valency was 3.1 for Si MgO and 2.6 for Si ZnO co-sputtered films when Si contents were 20%. Diffraction peaks of not Si-derived but less crystallized matrix were observed at low Si content ranges. Both films are seen to have structures with nanoparticle dispersion from TEM observation. The PL emission observed at 1.7 eVfor Si MgO and at2.0eV for Si ZnO is deduced to arise from the electron-hole recombination mechanism in SiO x at the interface, which is similar to the Si SiO 2 co-sputtered film.