Mean transverse energy of ultrananocrystalline diamond photocathode
- Illinois Inst. of Technology, Chicago, IL (United States)
- Univ. of Illinois, Chicago, IL (United States)
- Euclid TechLabs LLC, Bolingbrook, IL (United States)
- Michigan State Univ., East Lansing, MI (United States)
Nitrogen incorporated ultrananocrystalline diamond [(N)UNCD] could be an enabling material platform for injector photocathode applications due to its high emissivity. While the quantum efficiency (QE) of UNCD was reported by many groups, no experimental measurements of the intrinsic emittance/mean transverse energy (MTE) have been reported. Here, MTE measurement results for an (N)UNCD photocathode in the photon energy range from 4.41 to 5.26 eV are described. The MTE demonstrates no noticeable dependence on the photon energy, with an average value of 266 meV. This spectral behavior is shown not to be dependent upon physical or chemical surface roughness and inconsistent with low electron effective mass emission from graphitic grain boundaries but may be associated with emission from spatially confined states in the grain boundaries. Lastly, the combined effect of low and constant MTE and high QE, which increases with respect to the excess laser energy, may pave the way for bright UNCD photocathodes for electron injectors.
- Research Organization:
- Euclid Techlabs LLC, Cleveland, OH (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF)
- Grant/Contract Number:
- SC0013145; AC02-06CH11357; NSF-1739150; PHYS-1535279
- OSTI ID:
- 1611969
- Journal Information:
- Applied Physics Letters, Vol. 114, Issue 9; ISSN 0003-6951
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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