Dependencies of secondary electron yields on work function for metals by electron and ion bombardment

Secondary electron yields depending on work function were measured for 30 species of metal in ultrahigh vacuum by electron and ion bombardment. Secondary electron yields induced by electrons at 10 keV increase with work function, while those by Ar+ ions at 3 keV decrease with increasing work function. The opposite dependencies of secondary electron yields on work function between electron and ion bombardment are discussed on the basis of the different mechanisms of secondary electron emission, i.e., kinetic and potential emission for electron and ion bombardment, respectively. (C) 2000 American Institute of Physics. [S0003-6951(00)01023-8].