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

Stanley K H Pau, J. Kuhl, F. Scholz, V. Haerle, M. A. Khan, C. J. Sun

Research output: Contribution to journalArticle

36 Citations (Scopus)

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-μm-thick bulk samples or from exciton/free-carrier scattering. At low temperatures and low excitation intensities the dephasing time of the A exciton is as long as 3 ps and is most likely due to scattering by defects. At excitation densities above Nex = 5 × 1015 cm-3 exciton-exciton scattering becomes the dominant dephasing mechanism and a fifth-order diffraction signal is observed above Nex = 3 × 1016 cm-3.

Original languageEnglish (US)
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume56
Issue number20
StatePublished - 1997
Externally publishedYes

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Aluminum Oxide
Four wave mixing
Sapphire
Excitons
four-wave mixing
sapphire
excitons
Scattering
scattering
polaritons
excitation
Diffraction
Defects
propagation
LDS 751
Lasers
defects
decay
diffraction
lasers

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Femtosecond degenerate four-wave mixing of GaN on sapphire : Measurement of intrinsic exciton dephasing time. / Pau, Stanley K H; Kuhl, J.; Scholz, F.; Haerle, V.; Khan, M. A.; Sun, C. J.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 56, No. 20, 1997.

Research output: Contribution to journalArticle

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AU - Haerle, V.

AU - Khan, M. A.

AU - Sun, C. J.

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