Influence of electron beam and ultraviolet ozone irradiation on blue-emission properties of C_(60)-coupled porous silicon

摘要

Electron beam irradiation was carried out to change the surface structure of Si nanocrystals in C_(60)-coupled porous silicon with blue light emission at 460 nm. It was found that the photoluminescence (PL) intensities of the coupled system irradiated with an electron dose of 10~(15) cm~(-2) and energy of 0.5 MeV more than doubled compared to the untreated materials and then the intensities diminished with storage time in air. After 13 days, the PL intensities reached stable values that were higher than those observed from the untreated sample. Spectral analysis and ultraviolet ozone irradiation experiments on the coupled systems suggest that the formation of self-trapped excitons at the surfaces of the silicon nanocrystals with a higher density is responsible for the enhanced blue PL. Our technique provides an efficient way to improve the efficiency of blue light emission from these silicon nanostructures.