Studies of the work function of rare earth and other metal films

Rare earth metal films have been prepared in Ultra-high Vacuum (U.H.V.) and work function measurements made, in situ, by a vibrating capacitor technique. The effects of aging in U.H.V. and of atmospheric contamination have been studied. Measurements have been made on Gd above and below the Curie temperature, before and after annealing at 390K by means of a novel nichrome-film heater (developed for U.H.V. use). The resistivities of the rare earth films were determined by an in situ potential probe method in conjunction with interferometric thickness measurements. Work function measurements have also been made on other metal films and on silicon surfaces to provide data relevant to theoretical work on point-contact detectors for far infra-red radiation.