Electron emission from diamond induced by atomic and molecular ions

Abstract

Extremely large ion-induced electron emission (IIEE) yields, γ, defined as the number of emitted electrons per incident projectile, were previously reported by us for impingement of sub-mega electron volt light (H) and heavy (N and Ar) ions onto hydrogenated, boron-doped diamond surfaces. γ was found to decrease rapidly with increasing ion dose, presumably because of ion-damage related modification of the emitting material. In this work, we compare γ for molecular impingement (H 2 +, N 2 +) to that of the atom ion impingement (H +, N +) with the individual species having the same velocity. It is found that (i) the maximal IIEE yields (extrapolated to 0 dose) per atom for molecular impingement is smaller by 15–20% than that measured for the corresponding single ions. Yet they are still extremely large. (ii) The decay rates of γ per atom for molecular impingement are faster than those measured for the corresponding single ions, yet they still saturate at very high γ values. The present results bear on the physics of ion–solid interactions and on the applicability of diamond for the detection and counting of single ion and molecule.