Si-rich a-Si1-xCx thin films by d.c. magnetron co-sputtering of silicon and silicon carbide: Structural and optical properties

Si-rich hydrogenated amorphous silicon carbide (a-Si_1-xC_x:H) thin films with different carbon fractions were elaborated by a d.c. magnetron sputtering system. Their structural and optical properties were investigated by UV-visible spectrophotometry, infrared spectroscopy (FTIR), secondary ion mass spectroscopy (SIMS), Raman spectroscopy and photoluminescence (PL). The results show that the increase in the carbon fraction induces an increase in the optical gap (E_g) up to a maximum value of 2.53 eV, corresponding to a carbon fraction (x) of 0.25, and then E_g decreases to 1.76 eV corresponding to a carbon fraction x = 0.33.