DIAMOND PHOTOCATHODE Russian patent published in 2018 - IPC H01J40/06 H01J1/34 

FIELD: electrical equipment; optics.

SUBSTANCE: invention relates to photocathodes operating in the visible and ultraviolet spectral regions, which can be used in electrons photo injectors for wake type accelerators, free-electron lasers, as well as for electronic and optical conversion of signals in various electronic devices. According to invention, proposed is a diamond photocathode based on a multilayer structure of sequentially arranged monocrystalline diamond layers. Diamond photocathode contains single-crystal diamond layer (substrate), which is optically transparent to the input radiation, heavily doped by donors or acceptors layer, in which input radiation absorption and photoelectrons generation occurs; transport layer, through which the photoelectrons motion (diffusion and drift) to the surface and their thermalization takes place, as well as having the p-type conductivity surface layer with reduced output operation, which ensures the efficient photoelectrons emission into the vacuum and prevents the emitting surface charging. At that, a voltage can be applied to the transport layer, which facilitates the photoelectrons drift to the photocathode surface. Diamond photocathode has high quantum efficiency in the ultraviolet and visible regions of the spectrum (> 250 nm) and high-speed performance, it is capable to work stably for a long time with relatively low vacuum level of 10^-5–10^-6 Torr and high emission currents, has high thermal conductivity, which provides efficient heat dissipation and cooling of the photocathode, and is capable to emit the photoelectrons beams with small energy spread due to their thermalization in the transport layer.

EFFECT: diamond photocathode design provides good reproducibility of emission characteristics and uniformity of emission.

8 cl, 6 dwg