Diamond cold cathodes

Summary form only given. Substantial progress has been made in understanding the physics of diamond cold cathodes. Four distinct regions: the metal contact, bulk diamond, vacuum interface, and free space, exhibit distinct physical processes affecting the behaviour of the cathode. The contact region mediates the transfer of electrons and holes between the metal and the diamond. The bulk of the diamond limits the transport of carriers. Any dopants in this region will modify the fields throughout the diamond. The vacuum interface and the diamond termination at this interface control the emission into the vacuum, and impact the field in the diamond. Finally the electrons transit the vacuum region outside the diamond. Here, the electric field is set by the difference in potential between the anode and the diamond surface, which in turn depends on the charge distribution within the diamond. A number of diagnostics have been used to examine the characteristics of each region.