A combined approach to greatly enhancing the photoluminescence of Si nanocrystals embedded in SiO_2

摘要

An approach combining back- and front-side doping of Ce~(3+) in Si nanocrystals embedded in SiO_2 (nc-Si:SiO_2) with hydrogen passivation has been developed, which largely enhances the photoluminescence (PL) of Si nanocrystals. The sample of nc-Si:SiO_2 was prepared via a phase separation process of SiO thin film at 1100 deg C. For the back-side doping, a SiO_2 buffer layer was placed between the CeF_3 layer and SiO one, thus Ce~(3+) doping could be accomplished without disrupting the phase separation of SiO. The front-side doping was then followed by evaporating CeF_3 onto the front surface of the formed nc-Si:SiO_2, followed by diffusion annealing at 500 deg C. The double-side doping enhanced the PL intensity of Si nanocrystals by a factor of 7.3. After hydrogenation of the double-side doped sample, a 14.6-fold increase in the PL intensity was finally achieved.