Composite zinc/silicon nanocrystalline thin film: preparation, structures and the effect of oxidation on their photoluminescence

Abstract

Zinc/silicon nanocrystalline thin films were prepared by the pulsed laser deposition method in a vacuum chamber using a rotary target which exposed the zinc and silicon materials to the laser alternately. TEM, EDS, AFM, SIMS and XPS results show that the as-prepared sample was a mixture of silicon and zinc nanoparticles, which were only slightly oxidized. The existence of silicon nanocrystals was also confirmed by photoluminescence analysis. XPS results confirmed that, when the samples were annealed in the open but clean atmosphere, the extent of oxidation of the film increased with temperature. When the temperature was increased from room temperature to 500°C, the intensity of the photoluminescence peak from the nanosilicon crystals first increased, then decreased and finally disappeared. A new PL peak found in the wavelength region of 400-550 nm was attributed to ZnO nanoparticles formed by their interaction with silicon oxide. Our results confirmed that the interface effect between the Si and Zn nanoparticles strongly affects the PL of the interfacial ZnO nanoparticles.