Dresden 2006 – scientific programme
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HL: Halbleiterphysik
HL 50: Poster II
HL 50.95: Poster
Thursday, March 30, 2006, 16:30–19:00, P3
Engineering the multi-exciton spectra in wurtzite InN/GaN quantum dots — •Norman Baer, Stefan Schulz, Stefan Schumacher, Paul Gartner, Gerd Czycholl, and Frank Jahnke — Institute for Theoretical Physics, University of Bremen
The emission spectra of nitride based quantum dots (QDs) differ dramatically from those known from other III-V material systems. We use an atomistic description of the single-particle properties in InN/GaN QDs and combine them with a microscopic calculation of the Coulomb interaction effects. Details of a tight-binding (TB) study that fully incorporates the underlying wurtzite lattice structure and the induced electrostatic fields are presented. In the TB-model we use a sp3 basis set and calculate the internal fields via the solution of the Poisson equation. From the resulting TB-wave functions Coulomb- and dipole matrix elements are evaluated and enter the Full Configuration Interaction calculations. The effects of Coulomb correlations on the optical properties of the nitride system are investigated. In particular we study in detail the influence of the QD geometry and the effect of the strong built-in fields on the emission spectra. The dependency of the ground state symmetry as a function of the QD size and the resulting changes in the optical spectra are discussed, which allow to tailor the emission spectra.