We like to think that Saxet Surface Science has one of the most vigorous research programs in the field of photocathodes since RCA's heyday. Below are detailed some of our current activites. We presently have several research grants in the photocathode field.

• GaAs photoemitter environmental immunization decay
We have developed an activation procedure by which the reactivity to CO2, a principal cause of yield decay for GaAs photocathodes, is greatly reduced. The use of a second chemical in the activation process is responsible for the increased immunity of the activated surface. The best immunity was obtained by using this combination without any loss in near bandgap yield. Optimally activated photocathodes have nearly equal quantities of both chemicals. The plot to the right shows the effect of CO2 exposure on activated bulk GaAs using the standard and modified techniques.

• Amorphous silicon photoemitters
Saxet Surface Science is dedicated to the development of this exciting photoemitter. While it does not have the yield of other VIS-sensitive photocathodes, it has a greater immunity to vacuum environment interactions, whether in the form of residual gas neutrals or ions. The following photo shows the growth of amorphous silicon in our RF PECVD system. Due to its robustness and ease of growth on most surfaces, it may prove to be an ideal choice for use in RF guns for high energy accelerators and free electron laser source injectors.
• Photon-driven vacuum tubes
We have recently shown that our amorphous silicon photoemitters can be used as the electron source in vacuum tubes, a major advance in this nascent field. Such devices should exhibit advantages in speed and high voltage compatibility when contrasted with their solid-state equivalents. They will consume much less energy and run cooler than the old style, energy-hungry vacuum tubes, which employ thermionic electron sources.

• Technology transfer
Saxet Surface Science is presently embarking on a collaboration with a major photoemitter manufacturer to transfer Saxet Surface Science's advanced photoemitter preparation techniques into the manufacturing arena.