Ion-induced electron emission from boron-doped diamond: effect of surface hydrogenation and sample temperature

Extremely high ion-induced electron emission yields (gamma) from B-doped di amond films induced by impingement of 200-keV protons and 140-keV Ar ions ( gamma = 150 and gamma = 180, respectively) are reported. The dependence of gamma on target temperature, on total accumulated ion-dose and on surface t ermination (hydrogen- or oxygen-terminated) were studied. Very large gamma were found with fresh surfaces at elevated temperatures possibly due to rem oval of surface contaminants. Progressive ion bombardment severely deterior ated emission properties, presumably due to material modification (graphiti zation) in the case of Ar, but much less so for hydrogen ion bombardment. H eating the target (up to 500 degreesC) strongly inhibited degradation of ga mma after some initial degradation, but did not stop it completely. Oxygen- terminated diamond surfaces emitted approximately 30% less efficiently than hydrogen-terminated surfaces. Theoretical and practical implications of th ese findings are discussed. (C) 2001 Elsevier Science B.V. All rights reser ved.