Visible photoluminescence in Si+-implanted silica glass

Abstract

We have investigated visible photoluminescence excited by Ar‐ion laser (488 nm, 2.54 eV) at room temperature from Si⁺‐implanted silica glass, as‐implanted and after subsequent annealing in vacuum. We found two visible luminescence bands: one peaked around 2.0 eV, observed in as‐implanted specimens and annealed completely after heating to about 600 °C, the other peaked around 1.7 eV observed only after heating to about 1100 °C, the temperature at which Si segregates from SiO_x. It was found that the 2.0 eV band anneals parallel to the E’ centers, as detected by electron spin resonance studies. It was also found that Raman lines around 520 cm⁻¹, due to Si—Si bonds, grow and that interference patterns are induced by annealing Si⁺‐implanted silica glass. Based on these studies, we ascribe the 2.0 eV band to the electron‐hole recombination in Si‐rich SiO₂ and the 1.7 eV band to the electron‐hole recombination in the interface between the Si nanocrystal and the SiO₂ formed by segregation of crystalline Si from SiO_x.