The Effect of Average Grain Size on Polycrystalline Diamond Films

The work function of hydrogen-terminated, polycrystalline diamond was studied using ultraviolet photoelectron spectroscopy. Polycrystalline diamond films were deposited onto molybdenum substrates by electrophoresis for grain sizes ranging from 0.3 to 108 microns. The work function and electron affinity were measured using 21.2 eV photons from a helium plasma source. The films were characterized by x-ray photoelectron spectroscopy to determine elemental composition and the sp2/sp3 carbon fraction. The percentage of (111) diamond was determined by x-ray diffraction, and scanning electron microscopy was performed to determine average grain size. The measured work function has a maximum of 5.1 eV at 0.3 microns, and decreases to 3.2 eV at approximately 4 microns. Then the work function increases with increasing grain size to 4.0 eV at 15 microns and then asymptotically approaches the 4.8 eV work function of single crystal diamond at 108 microns. These results are consistent with a 3-component model in which the work function is controlled by single-crystal (111) diamond at larger grain sizes, graphitic carbon at smaller grain sizes, and by the electron affinity for the intervening grain sizes.

Grantor dc:publisher

University of North Texas

Year dc:date

2002

Author dc:creator

• Abbott, Patrick Roland

Contributors dc:contributor

• Golden, David E.
• Gnade, Bruce
• Kelber, Jeffry A.
• Hu, Zhibing

• Diamond thin films.
• Electrons -- Emission.
• grain size
• work function
• diamond films
• thin films
• electron affinity

Statement dc:rights

• Public
• Copyright
• Abbott, Patrick Roland
• Copyright is held by the author, unless otherwise noted. All rights reserved.

Language dc:language

English

Identifier

oclc: 54674231
https://digital.library.unt.edu/ark:/67531/metadc3164/
ark: ark:/67531/metadc3164

OAI identifier oai:identifier

info:ark/67531/metadc3164