Exceptionally high ion-induced electron emission yield from hydrogenated diamond and its decay

Abstract

Extremely high ion-induced electron emission (IIEE) yields-γ-(exceeding 400) are measured for boron-doped hydrogenated diamond, bombarded with sub-MeV Ar ions. These high values are found to rapidly diminish with an increasing number of ions impinging on the diamond surface, eventually reaching the low values of IIEE (of the order of 5) found for graphite and most materials. This reduction is shown to be caused by two processes: One, which affects a very large area around each ion-impingement point (and thus causes the rapid reduction in γ), may be either due to electron transport limitations caused by point defects introduced by the ion during their slowing down in the diamond or to surface hydrogen loss induced by the outgoing electrons; the second, more gradual loss process, is attributed to local graphitization around each ion track. A material with such a high electron-emission yield as the presently studied B-doped hydrogenated diamond, may find an application in the detection and counting of single ions or molecules, as needed mainly for biological applications.