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

The absolute total electron yield (TEY) of copper and gold at the (111) sur face of single crystals in the photon energy range between 40 and 1500 eV w as measured with estimated relative uncertainties lower than 4%. Our data a re up to twice as high as data found in the literature. A widely used appro ximation is that the TEY is proportional to the product of the linear absor ption coefficient mu and the photon energy hv. To test this model we determ ined the absorption coefficient independently by measuring the transmittanc e of polyimide films covered either with thin gold or copper layers. For ou r model of the TEY the electron escape depth had to be known, which was det ermined 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 descript ion of the primary and secondary electron contribution to the total electro n yield has been developed. Good agreement between the calculated and the m easured TEY was achieved. (C) 1999 Elsevier Science B.V. All rights reserve d.