- Author
-
Robins, L. H.
|
Tjossem, P. J. H.
|
Smyth, K. C.
|
Barnes, Y.
|
Farabaugh, E. N.
|
Feldman, A.
- Title
- Photoluminescence Excitation by Band-Gap Optical Absorption in Chemical Vapor Decompositon Diamond Films.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
- Journal
-
Journal of Applied Physics,
Vol. 69,
No. 6,
3702-3708,
March 15, 1991
- Keywords
-
vapors
|
films
|
luminescence
- Abstract
- Photoluminescence excitation (PLE) spectra at photon energies near the indirect band gap of diamond have been obtained for diamond films grown by the filament-assisted chemical vapor deposition (CVD) method. The PLE intensity was observed to increase abruptly with photon energy above 5.5 eV. This increase coincides with the onset of phonon-emission-assisted interband absorption, which was observed independently by diffuse transmittance measurements. A lower-energy PLE threshold at approx. 5.25 eV, which coincides approximately with the onset of phonon-absorption-assisted interband absorption, was observed in the spectrum of a gem-quality natural diamond, but not in the spectra of the CVD-grown filsm. Emission spectra of the luminescence excited by above-band-gap photons have features similar to luminescence spectra of the same specimens excited by 20-keV electrons. The spectrally integrated intensities of the luminescence excited by above-band-gap photons and by electrons were found to vary from specimen to specimen in a linearly related manner, suggesting that similar recombination processes occur in both cases.