Journal
DIAMOND AND RELATED MATERIALS
Volume 18, Issue 5-8, Pages 789-791Publisher
ELSEVIER SCIENCE SA
DOI: 10.1016/j.diamond.2009.01.024
Keywords
diamond; chemical vapor deposition; doping; phosphorus
Ask authors/readers for more resources
Thermionic electron emitters are a key component in applications ranging from travelling wave tubes for communications, space propulsion and direct energy conversion. As the conventional approach based on metallic emitters requires high operating temperatures the negative electron affinity (NEA) characteristic of diamond surfaces in conjunction with suitable donors would allow an electronic structure corresponding to a low effective work function. We have thus prepared phosphorus-doped polycrystalline diamond films on metallic substrates by plasma assisted chemical vapor deposition where an NEA surface characteristics was induced by exposure of the film surface to a hydrogen plasma. Thermionic electron emission measurements in an UHV environment were conducted with respect to the Richardson-Dushman relation observing an emission current at temperatures <375 degrees C. Measurements were terminated at 765 degrees C without significant reduction in the electron emission current indicating a stable hydrogen passivation of the diamond surface. A fit of the emission data to the Richardson equation allowed for the extraction of emission parameters where the value of the materials work function was evaluated to 0.9 eV. This value could well be the lowest measured work function of any known material. Published by Elsevier B.V.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available