Absolute total electron yield of Au(111) and Cu(111) surfaces

The absolute total electron yield (TEY) of copper and gold at the (111) surface of single crystals in the photon energy range between 40 and 1500 eV was measured with estimated relative uncertainties lower than 4%. Our data are up to twice as high as data found in the literature. A widely used approximation is that the TEY is proportional to the product of the linear absorption coefficient mu and the photon energy hv. To test this model we determined the absorption coefficient independently by measuring the transmittance of polyimide films covered either with thin gold or copper layers. For our model of the TEY the electron escape depth had to be known, which was determined by evaporating thin gold films only 0.2 to 10 nm in thickness onto the Cu(111) surface and vice versa. Using these data an analytical description of the primary and secondary electron contribution to the total electron yield has been developed. Good agreement between the calculated and the measured TEY was achieved. (C) 1999 Elsevier Science B.V. All rights reserved.