Cathode sputtering and the resulting formation of carbon nanometer-size dust

Nanometer-size particles are produced in parallel electrode glow discharges. Supersaturated carbon vapor produced by the sputtering of a graphite cathode is at the origin of their formation. In this context, the energy distribution and the flux of the sputtering particles are estimated. The energy distribution of the emitted carbon atoms is also evaluated as a function of the distance to the cathode, taking into account the collisions with the discharge gas atoms. These collisions induce the carbon vapor cooling and then, a nucleation-condensation phase giving rise to dust precursor clusters. A linear scaling law of growth is established experimentally as a function of time when the dust size is higher than 20 nm. Within the considered time range, this scaling law shows that the growth comes from neutral deposition on the dust surface. (c) 2007 American Institute of Physics.