Photoluminescence properties of SiO_x thin films prepared by reactive electron beam evaporation from SiO and silica nanoparticles

摘要

A simple reactive evaporation technique is proposed to obtain highly efficient light emitting Si nanostructures. It is shown that structurally homogeneous SiO_x thin films are synthesized by a reactive electron beam evaporation from a mixture of SiO and silica nanoparticles. These SiO_x thin films result in the formation of Si nanocrystals on annealing under Ar atmosphere, exhibiting efficient photoluminescence (PL) emission. The composition of SiO_x thin films is varied by changing the molar concentration of silica in the mixture. X-ray photoelectron spectroscopy and Fourier transform infrared measurements demonstrate that a chemical reaction between SiO and silica nanoparticles occurs during electron beam irradiation, creating evaporated species in the form of SiO_y (1 < y < 2). The pivotal role of the homogeneous microscopic structure of as-deposited thin films on the resulting PL yield after annealing is proposed.