Raman and PEELS Studies on Magnetron Sputtered a-C.

Amorphous carbon coatings (a-C, a-C:H) of less than 100 nm thick were deposited on KBr pellets and silicon wafer substrate via magnetron sputtering of graphite target in argon, argon/hydrogen and argon/nitrogen atmosphere. Parallel electron energy loss spectroscopy (PEELS) analysis was used to quantify the sp²/sp³ bonding in carbon films. Stand-alone films of amorphous carbon were produced by sputtering onto compressed KBr pellets and then floating off in distilled water for PEELS study. Raman spectroscopy was used to measure the peak intensity ratio of D-band to that of the G-band (I[sub d]/I[sub g]). It shows that higher sp³ fraction often associates with lower Raman peak ratio I[sub d]/I[sub g]. At the same time, G-band peak position P[sub g] decreases while sp³ fraction increases. [ABSTRACT FROM AUTHOR]