White light emission from amorphous silicon oxycarbide (a-SiCxOy) thin films: Role of composition and postdeposition annealing

The effects of carbon and postdeposition annealing on white luminescence are studied in amorphous silicon oxycarbide (a-SiCxOy) films grown by chemical vapor deposition. The films showed strong room-temperature luminescence in a broad spectral range from blue-violet to near infrared, depending on excitation energy. Photoluminescence (PL) intensity exhibited good correlation with Si-O-C bond concentration. At low C (< 5%), matrix PL was completely quenched after annealing in O-2 even at 500 degrees C. PL was unaffected by O-2 annealing at higher C, and could be enhanced when excited by an ultraviolet laser. These findings are correlated to C- and Si-related O defect centers as luminescence sources in a-SiCxOy. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3482938]