Ion-induced kinetic electron emission from HOPG with different surface orientation

摘要

Total electron emission yields for impact of H+, H-2(+), C+, N+, O+ and Ar+ ions (impact energy 2 - 10 keV) on clean highly oriented pyrolytic graphite ( HOPG) have been measured. An enhancement in the electron yield of more than a factor of 2 is found when comparing results for differently oriented HOPG surfaces ( orientation of the graphite layers with respect to the surface). By analyzing these data we elucidate the influence of electron transport on kinetic electron emission and derive direction-dependent mean escape depths for low-energy electrons.