Subpicosecond time-resolved roman studies of nonequilibrium excitations in wurtzite GaN

Kong-Thon Tsen, R. P. Joshi, D. K. Ferry, A. Botchkarev, B. Sverdlov, A. Salvador, H. Morkoc

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Non-equilibrium electron distributions as well as phonon dynamics in wurtzite GaN have been measured by subpicosecond time-resolved Raman spectroscopy. Our experimental results have demonstrated that for electron densities n ≥ 5 × l0 17cm -3, the non-equilibrium electron distributions in wurtzite GaN can be very well described by Fermi-Dirac distribution functions with the temperature of electrons substantially higher than that of the lattice. The population relaxation time of longitudinal optical phonons was directly measured to be τ = 5 ± 1 ps at T = 25 K. The experimental results on the temperature dependence of the lifetime of longitudinal optical phonons suggest that the primary decay channels for these phonons are the decay into (1) one transverse optical phonon and one high energy, longitudinal or transverse acoustical phonons; and (2) one transverse optical phonon and one E 2 phonon.

Original languageEnglish (US)
Title of host publicationMaterials Research Society Symposium - Proceedings
EditorsF.A. Ponce, T.D. Moustakas, I. Akasaki, B.A. Monemar
PublisherMaterials Research Society
Pages737-742
Number of pages6
Volume449
StatePublished - 1997
EventProceedings of the 1996 MRS Fall Symposium - Boston, MA, USA
Duration: Dec 2 1996Dec 6 1996

Other

OtherProceedings of the 1996 MRS Fall Symposium
CityBoston, MA, USA
Period12/2/9612/6/96

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Phonons
Electrons
Relaxation time
Distribution functions
Carrier concentration
Raman spectroscopy
Temperature

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

Cite this

Tsen, K-T., Joshi, R. P., Ferry, D. K., Botchkarev, A., Sverdlov, B., Salvador, A., & Morkoc, H. (1997). Subpicosecond time-resolved roman studies of nonequilibrium excitations in wurtzite GaN. In F. A. Ponce, T. D. Moustakas, I. Akasaki, & B. A. Monemar (Eds.), Materials Research Society Symposium - Proceedings (Vol. 449, pp. 737-742). Materials Research Society.

Subpicosecond time-resolved roman studies of nonequilibrium excitations in wurtzite GaN. / Tsen, Kong-Thon; Joshi, R. P.; Ferry, D. K.; Botchkarev, A.; Sverdlov, B.; Salvador, A.; Morkoc, H.

Materials Research Society Symposium - Proceedings. ed. / F.A. Ponce; T.D. Moustakas; I. Akasaki; B.A. Monemar. Vol. 449 Materials Research Society, 1997. p. 737-742.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Tsen, K-T, Joshi, RP, Ferry, DK, Botchkarev, A, Sverdlov, B, Salvador, A & Morkoc, H 1997, Subpicosecond time-resolved roman studies of nonequilibrium excitations in wurtzite GaN. in FA Ponce, TD Moustakas, I Akasaki & BA Monemar (eds), Materials Research Society Symposium - Proceedings. vol. 449, Materials Research Society, pp. 737-742, Proceedings of the 1996 MRS Fall Symposium, Boston, MA, USA, 12/2/96.
Tsen K-T, Joshi RP, Ferry DK, Botchkarev A, Sverdlov B, Salvador A et al. Subpicosecond time-resolved roman studies of nonequilibrium excitations in wurtzite GaN. In Ponce FA, Moustakas TD, Akasaki I, Monemar BA, editors, Materials Research Society Symposium - Proceedings. Vol. 449. Materials Research Society. 1997. p. 737-742
Tsen, Kong-Thon ; Joshi, R. P. ; Ferry, D. K. ; Botchkarev, A. ; Sverdlov, B. ; Salvador, A. ; Morkoc, H. / Subpicosecond time-resolved roman studies of nonequilibrium excitations in wurtzite GaN. Materials Research Society Symposium - Proceedings. editor / F.A. Ponce ; T.D. Moustakas ; I. Akasaki ; B.A. Monemar. Vol. 449 Materials Research Society, 1997. pp. 737-742
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AB - Non-equilibrium electron distributions as well as phonon dynamics in wurtzite GaN have been measured by subpicosecond time-resolved Raman spectroscopy. Our experimental results have demonstrated that for electron densities n ≥ 5 × l0 17cm -3, the non-equilibrium electron distributions in wurtzite GaN can be very well described by Fermi-Dirac distribution functions with the temperature of electrons substantially higher than that of the lattice. The population relaxation time of longitudinal optical phonons was directly measured to be τ = 5 ± 1 ps at T = 25 K. The experimental results on the temperature dependence of the lifetime of longitudinal optical phonons suggest that the primary decay channels for these phonons are the decay into (1) one transverse optical phonon and one high energy, longitudinal or transverse acoustical phonons; and (2) one transverse optical phonon and one E 2 phonon.

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