IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Thin Films Friday Sessions
       Session TF-FrM

Paper TF-FrM4
Electron Transmission in Thin B-doped CVD Diamond Films

Friday, November 2, 2001, 9:20 am, Room 123

Session: Diamond and Related Materials
Presenter: J.E. Yater, Naval Research Laboratory
Authors: J.E. Yater, Naval Research Laboratory
A. Shih, Naval Research Laboratory
J.E. Butler, Naval Research Laboratory
P.E. Pehrsson, Naval Research Laboratory
Correspondent: Click to Email
Diamond is a promising cold emitter material for vacuum electron devices because of the negative electron affinity (NEA) observed at specific surfaces. While the NEA properties have been studied extensively, the cold emission process in diamond has not been well characterized. In this study, we inject electrons into thin CVD diamond films using a 0-20 keV electron gun, and we examine the transport and emission of low-energy secondary electrons in transmission measurements. In particular, we measure the intensity and energy distribution of transmitted electrons as a function of incident beam parameters (energy, current) and material properties (film thickness, doping concentration). A series of B-doped CVD diamond films has been grown with thickness between 1 and 7 microns, with the first sample being a lightly-doped, 2.5-micron-thick film with a NEA emitting surface (as indicated by yield measurements of ~20). For beam energies above 13 keV, the transmitted intensity is sharply peaked ~0.60 eV above the emission onset with a FWHM of ~0.60 eV. At constant beam energy (or current), the peak width, position, and emission onset remain constant as the beam current (or energy) is increased, and the peak is very similar to that obtained in reflection measurements. At beam energies below 13 keV, the transmission peak is much broader and less intense. It is possible that the light B doping impacts the transport of electrons to the front surface since a sharp peak was observed at all energies in a previous study of a more conductive 2-micron-thick film. Our ongoing studies continue to examine the role of doping and film thickness on the transmission properties of diamond films.