Optical emission from silicon-based SiO2 islands fabricated by anodic alumina templates

We have investigated the photoluminescence spectra of silicon-based nanoscale SiO2 islands obtained by anodization of silicon-based aluminum membranes in a 0.3m sulfuric acid solution under a constant voltage of 25V. Two ultraviolet emission bands were observed at 290 and 370nm. After annealing the samples in 900°C in O2, the 290nm band vanishes, but the 370nm band still exists. We suggest that the 290nm band originates from optical transition in the E′ centers in the SiO2 islands according to its annealing behavior. The 370nm band is considered to be from Al-related luminescence centers, [AlO4]0, because a decrease of intensity of the 370nm band is in agreement with that of amount of the Al ion impurities located in the SiO2 islands. This work shows a clear understanding of the light-emitting mechanism of silicon-based SiO2 island array. The obtained result can be expected to have important applications in modem optoelectronics.