Oxidation Unsusceptible Photocathodes for Near-UV

The overall aim is to identify a suitable material for photocathodes that produces a sufficiently high flow
of electrons, despite limited oxidisation during operational life in low vacuum. The most promising
strategies and materials were investigated. The strategy was, to use elements/alloys and their oxides that
have a suitable UV LED emission work function and use an alloy with a low work function element. The
materials selected for study were aluminium alloy 2014, aluminium alloy 2060, manganese, silver and
pure titanium. Magnetron sputtering was used to create the thin films of materials for study. The
photoelectron current generated when UV light was shone on the film was measured and recorded over
24 h in high and low vacuum. In conclusion, Mn and alloy 2014 produced poor results, alloy 2060 was
an improvement, but did not produce a high enough photocurrent until more silver was added. Pure
titanium results were the similar to alloy 2014. Other options such as nitride film and nickel were tested
with little positive results. Recommendations’ are to explore alloy 2060 with more silver and titanium,
look at copper, silver and investigate nitride films further.