Synthesis and Characterization of Self-Assembled ZnO Nanoparticles Embedded Within a SiO₂ Matrix Deposited on (111) p-Type Silicon By Reactive RF Sputtering Using Metallic Zinc Target As Precursor

The results of the synthesis and characterization of self-assembled ZnO nanoparticles (NP) embedded within a SiO₂ matrix deposited on (111) p-type silicon by reactive radio frequency sputtering are reported. Synthesis consists in a sequential deposit of SiO₂/metallic-Zn/SiO₂/SiO₂ layers, using argon and oxygen as the working atmosphere at a substrate temperature of 400°C. ZnO NP were nucleated at valleys of the first rough SiO₂ layer by the action of the reactive atmosphere and Zn atoms coming from the sputtered target. Three different deposition times for the zinc interlayer were studied. Scanning electron microscopy shows that films have uniform topography and transmission electron microscopy indicates the presence of NP with sizes around 10 nm. The successful production of ZnO is corroborated by x-ray photoemission spectroscopy studies. Secondary ion mass spectroscopy shows a spatial distribution of zinc depending on the thickness of the zinc interlayer, ZnO NP follow a similar distribution. Electrical transport studies have shown the formation of a rectifying structure between the layer and silicon substrate. Spectral response is observed with a wavelength distribution depending on the zinc interlayer thickness and probably due to the formation of ZnO NP of different sizes.