THE STABLE BLUE AND UNSTABLE UV PHOTOLUMINESCENCE FROM CARBON NANOCLUSTERS EMBEDDED IN SIO2 MATRICES

Strong and stable blue photoluminescence (PL) from annealed C clusters embedded in SiO2 (deposited by r.f.-sputtering) was recorded, under e xcitation power on a scale of mu W cm(-2). UV PL was also recorded fro m about half of the annealed samples, But this was not stable - the in tensity decayed with time. Carbon and oxygen K-edge XAFS (X-ray absorp tion fine structure) suggest that (1) the nanoclusters present are C-b ased materials, (2) the luminescent materials probably involve pi bond ed carbon. The size distributions of the nanoclusters obtained by TEM suggest that a quantum-confined size effect can also apply to the blue PL. Copyright (C) 1996 Elsevier Science Ltd