Photon emission from clean and oxygenated Si and SiO2 surfaces bombarded by 5Â keV krypton ions

The effect of oxygen on the light emission from a Si (1 0 0) semiconductor bombarded by energetic Kr+ ions has been studied in the 200-300 nm wavelength range. The influence of oxygen was verified by studying the optical spectra of SiO2 bombarded under similar experimental conditions. It has been found that the measured intensities of the emitted photons are always higher in the presence of oxygen, even higher than those obtained for SiO2. The electron-transfer model can explain our experimental observations. We do believe that in the presence of oxygen, an intermediate structure of silicon sub-oxide SiOX<2 is formed on silicon surface, which is responsible for the increase of photon emission. In addition, the radiative dissociation process and breaking of chemical bond seems contribute to the enhancement of emitted photons intensity.