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Secondary-electron-emission current measured from high-purity, single-crystal CVD diamond is found to increase when 3.1-eV photons are incident on the hydrogenated surface. Energy spectra indicate that the sub-gap illumination causes the band levels to shift in the bulk, thereby reducing the upwards band bending at the pinned surface.
We are developing a vacuum electron source using electrons transmitted through thin films of diamond. Calculations suggest this cold electron source is capable of providing total average currents in excess of 1A as well as energy spread below 0.5 eV and current densities roughly 100 times higher than conventional dispenser cathodes. We are growing diamond films with excellent quality and developing...
We report progress in mounting small thin diamond sheets over holes in larger substrates in a manner that allows electron beam amplification. In addition to a physical mount, our bonding method must be compatible with the creation and maintenance of the negative electron affinity surface and operation at elevated temperatures. We use a transient liquid phase bonding method wherein the constituent...
A diamond current amplifier is being developed that can be biased to generate an internal electric field needed for high transport efficiency and emission gain. In the process, a bonded diamond structure has been successfully fabricated that provides mechanical support for the microns-thick diamond film and that allows for the use of processing techniques needed to fabricate the biased device. Emission...
Free Electron Lasers (FELs) make significant demands on the photocathode / drive laser used to generate electron bunches, but no photocathode source simultaneously satisfies needed demands of lifetime, quantum efficiency, and response. High gain mm-wave (and beyond) amplifiers make analogous demands. A diamond current amplifier may enable progress by exploiting the high yield associated with secondary...
We report on photoemission images from NEA diamond using sub-bandgap and near-bandgap photon energies. Emission can be stimulated with photon wavelengths as low as 365 nm, but the low-energy emission disappears after heating the diamond to 700°C, while emission stimulated with 254 and 224 nm photons remains. In both cases the emission occurs only where the concentration of bulk point defects is low...
Secondary-electron-emission measurements are used to examine the transport and emission characteristics of an 8.3-micron-thick diamond amplifier film. Superior transport and emission properties are confirmed for the single-crystal CVD diamond compared to previously-studied polycrystalline diamond. In particular, low-energy secondary electrons are emitted from the conduction band even after diffusing...
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