PEEM is a suitable tool for absolute work function measurements

Abstract

Abstract Based on Einstein's photoelectric principle, the absolute work function was measured with a special modified photoemission electron microscope. The work function of the sample was determined by measuring the threshold of the photoelectron emission. The wavelength of ultraviolet rays was swept with an energy resolution of 1 nm. The numbers of excited electrons were counted by the counting system, using an output of a CCD camera to observe the spots on the fluorescent screen. The typical system background in the absence of UV light was measured from 0.1 to 0.4 cps. The photoemission threshold was determined by the intersection of the background and the signal in a semi‐log plot. The tentative work function of high‐purity single‐crystals of silver ((100), (110), (111)) and polycrystalline silver have been measured at 300 K to be 4.34(3), 4.25(3), 4.45(3) and 4.32(3) eV, respectively. Copyright © 2005 John Wiley & Sons, Ltd.