Femtosecond degenerate four-wave mixing of GaN on sapphire: Measurement of intrinsic exciton dephasing time

S. Pau, J. Kuhl, F. Scholz, V. Haerle

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

We describe time-integrated and spectrally resolved degenerate four-wave mixing (DFWM) on hexagonal GaN on sapphire for different laser energies and intensities. Our measured DFWM signal decays exhibit no contributions originating from polariton propagation effects in the 1- to 3-(Formula presented)m-thick bulk samples or from exciton/free-carrier scattering. At low temperatures and low excitation intensities the dephasing time of the (Formula presented) exciton is as long as 3 ps and is most likely due to scattering by defects. At excitation densities above (Formula presented) exciton-exciton scattering becomes the dominant dephasing mechanism and a fifth-order diffraction signal is observed above (Formula presented).

Original languageEnglish (US)
Pages (from-to)R12718-R12721
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume56
Issue number20
DOIs
StatePublished - Jan 1 1997
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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