Influence of oxides on the field emission of molybdenum

Molybdenum is widely used in fundamental research and industry, for example as substrate for photocathodes or electrode material in DC photoelectron guns. Usually, Mo is heated in situ to several hundred degrees to achieve an oxygen free surface for the photocathode deposition or to reduce the surface outgassing rate in the electron gun. Since enhanced field emission (EFE) is often observed there, we have investigated the influence of oxides on the EFE of Mo by means of a field emission scanning microscope (FESM) and x-ray photoelectron spectroscopy (XPS).