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Technology Commercialization and Partnerships Division

Planer field emitters and high efficiency photocathodes based on ultrananocrystalline diamond (ANL-IN-14-106)

A method of forming a field emitter comprises disposing a first layer on a substrate

The first layer is seeded with nanodiamond particles. The substrate with the first layer disposed thereon is maintained at a first temperature and a first pressure in a mixture of gases which includes nitrogen. The first layer is exposed to a microwave plasma to form a nitrogen doped ultrananocrystalline diamond film on the first layer, which has a percentage of nitrogen in the range of about 0.05 atom % to about 0.5 atom %. The field emitter has about 1012 to about 1014 emitting sites per cm2. A photocathode can also be formed similarly by forming a nitrogen doped ultrananocrystalline diamond film on a substrate similar to the field emitter, and then hydrogen terminating the film. The photocathode is responsive to near ultraviolet light as well as to visible light.

Benefits

  • Prototype planer filed emission based electron source for RF injectors in accelerators 
  • At surface gradients 4565 MV/m, peak currents of 180mA were achieved. 
  • Good operation at moderate high vacuum (10-6 Torr)