Sputtering of graphite in pulsed and continuous arc and spark discharges

The environment that leads to the sputtering of graphite electrodes and formation of carbonaceous discharge has been studied with emission spectroscopy. Population level densities, excitation & vibrational temperatures and electron densities have been obtained from a set of three ion sources. The sources operate in continuous and pulsed discharge modes. The sputtered species include monatomic, diatomic and higher carbon clusters. The main sputtered species are excited and ionized C1 (CI, CII, respectively) and C2. In the continuous arc discharge the vibrational temperature derived from the Swan band of C2 is ∼10,000 K, whereas, in the pulsed arc the excitation temperature of Neon is ∼11,000 K. The spark discharge yields an average excitation temperature of CI and NI ∼ 5500 K.