- 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.