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HL: Halbleiterphysik

HL 17: Poster Ib

HL 17.53: Poster

Friday, March 4, 2005, 16:30–19:00, Poster TU F

Studies of the local vibrational N-mode in III-N-V dilute nitrides by Raman spectroscopy — •M. Güngerich, P.J. Klar, W. Heimbrodt, B. Kunert, K. Volz, and W. Stolz — Department of Physics and Material Sciences Center, Philipps-University of Marburg, Germany

The local environment of the nitrogen atom is of crucial importance for the global electronic structure changes of the III-V host, i.e. the strength of the local perturbation at the N-site due to the differences in size and electronegativity between the N atom and the anion it replaces determines the magnitude of the band structure changes. The phonons of the dilute nitrides exhibit a two-mode behaviour. A local N-mode is observed in addition to the host-like modes. The local N-mode is a useful probe of the local N-environment. We study the frequency of the N-related mode in various III-N-V alloys, i.e. GaNAs, GaNSb, GaNP, at ambient pressure and at hydrostatic pressures up to 20 GPa yielding information about the Ga-N bond strength in a wide range of lattice constants.