Comparative investigations of surface structure, photoluminescence and its excitation in silicon wires

Abstract

The dependence of the photoluminescence (PL) and PL excitation spectra on the porous silicon top surface structure and the oxide composition on it has been investigated. Researches were carried out using the following methods: PL, PL excitation, electron paramagnetic resonance, atomic force microscope and X-ray photoelectron emission spectroscopy. Results indicate a direct correlation between the suboxide content and roughness structure on the surface with PL intensity. No correlation was noted between the PL intensity and the concentration of Si dangling bonds (non-radiative recombination centers). These results have given further support to a suboxide-related color center on the Si/SiOx interface as the source of the intense red luminescence of silicon wires.