Effect of internal absorption on cathodoluminescence from GaN
Klaus Knobloch, Piotr Perlin , Joachim Krueger, Eicke R. Weber
University of California at Berkeley, Department of Materials Science and Mineral Engineering
Christian Kisielowski
NCEM, Lawrence Berkeley Laboratory
This article was received on January 27, 1998 and
accepted on February 24, 1998. Abstract
We
have studied optical properties of GaN grown on sapphire by metalorganic
chemical vapor deposition in the near band-edge energy range by
cathodoluminescence. A large shift of the band-edge luminescence to lower
energies is induced by increasing the beam energy. The free exciton position
shifts about 20 meV when the beam energy is increased from 5 keV to 25 keV at
room-temperature. The effect is explained by internal absorption caused by an
exponential absorption tail at the band-edge. An Urbach parameter of about 30
to 40 meV for the exponential band-tail in our samples is estimated by
comparing experimental with simulated spectra.Outline
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Cite this article as: MRS Internet J. Nitride Semicond. Res. 3, 4(1998).
last updated February 25, 1998 2:15:34 PM.© 1998 The Materials Research Society
