Improvement in photoluminescence efficiency of SiO2 films containing Si nanocrystals by P doping: An electron spin resonance study

SiO2 and phosphosilicate glass (PSG) films containing Si nanocrystals (nc-S i) as small as a few nanometers were studied by electron spin resonance (ES R) and photoluminescence (PL), and the correlation between the two measurem ents was examined. It is shown that the incorporation of nc-Si in SiO2 resu lts in the drastic increase in the ESR signal; the signal is assigned to th e Si dangling bonds at the interfaces between nc-Si and matrices (P-b cente rs). The ESR signal becomes weaker by doping P into SiO2 matrices, i.e., by using PSG as matrices. By increasing the P concentration, the ESR signal d ecreases further. By decreasing the ESR signal, the low-energy PL peak at 0 .9 eV decreases, while the band-edge PL at 1.4 eV increases. These results suggest that the 0.9 eV peak is related to P-b centers, and that the decrea se in the density of the P-b centers by P doping brings about an improvemen t in the band-edge PL efficiency of nc-Si. (C) 2000 American Institute of P hysics. [S0021-8979(00)07104-8].