Evidence of photoluminescence related to subsurface Si-O-Si bonds in sputtered silicon nanoparticles

We have prepared silicon nanoparticles by depositing the de sputtered Si ma terial on the cooled surface of a liquid-nitrogen-cooled trap. The photolum inescence in the region of 300-550 nm is found to be independent of the sur face chemical structure of the particles. FTIR investigations suggest that the photoluminescence peak is related to the Si-O-Si bonds whose stretching vibration wavenumber is about 1080 cm(-1). The results show a definite cor respondence between the photoluminescence intensities and the 1080 cm(-1) F TIR peaks for the different annealed samples. Moreover, this 1080 cm(-1) FT IR vibration species arises not from the surface layer but from the deeper subsurface layer of the particles, which explains why the photoluminescence is stable and fairly independent of the oxidation of the surface Si bonds through aging or annealing in the atmosphere. (C) 2000 Elsevier Science Ltd . All rights reserved.