Swift chemical sputtering of amorphous hydrogenated carbon - art. no. 195415

Ion bombardment of carbon materials is known to cause erosion with energies far below the threshold energy of physical sputtering, as well as at tempe ratures below the threshold of thermal desorption. Generally regarded as ch emical sputtering, this effect, and factors contributing to it, are not wel l understood. We use classical molecular-dynamics simulations, capable of r ealistically describing bond formation and breaking, to study amorphous hyd rogenated carbon surfaces under low-energy hydrogen bombardment. We present a swift chemical sputtering mechanism which can explain the experimentally observed characteristics of erosion by low-energy ion irradiation. We also show how the difference in the surface hydrogen concentration and carbon c oordination fractions at various temperatures affect the carbon sputtering yield.