Strong photoluminescence in ammonia plasma treated amorphous-SiC thin films deposited by laser ablation

Amorphous SiC films have been deposited by pulsed laser ablation on silicon substrates. Photoluminescence (PL) studies showed two broad bands with peaks at 1.34 and 1.72 eV for these unhydrogenated films. On NH3 passivation the intensity of the 1.34 eV peak increased by a large factor of 40-50 with full width at half-maximum (FWHM) decreasing to 13.5 meV at 12 K. The activation energy of this level was found to be 24 meV. These results are in contrast with those from unhydrogenated a-Si. A possible mechanism responsible for PL enhancement is discussed