Ion beam synthesis of Si nanocrystals in silicon dioxide and sapphire matrices-the photoluminescence study

The photoluminescence (PL) of Si+-implanted SiO2 thermal films and (11¯02) sapphire substrates was studied for wide ranges of ion doses and annealing temperatures (Tann). The regularities of the PL at 780 nm from Si nanocrystals (NC) embedded in SiO2 matrix for Tann=1000-1200°C are described based on a model that takes into account coalescence of nearest NCs and dependence of radiative recombination rate on the NC size. Two PL bands found in Si+ implanted Al2O3 before and/or after annealing (Tann=500-1100°C) are compared with those from Ar+-implanted samples and referred to the emission from Si NCs and defects.