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HL: Halbleiterphysik

HL 40: Quantum dots and wires: Optical properties III

HL 40.9: Talk

Thursday, March 30, 2006, 13:00–13:15, POT 151

Optical and electronic properties of self-organized wurtzite InN/GaN quantum dots — •Stefan Schulz, Norman Baer, Stefan Schumacher, Paul Gartner, Frank Jahnke, and Gerd Czycholl — Institute for Theoretical Physics, University of Bremen

In recent years, semiconductor quantum dots (QDs) have been the subject of intense experimental and theoretical research. As a new material system, group-III nitride based devices are of particular interest due to their wide range of emission frequencies from red to ultraviolet and their potential for high-power electronic applications.

We investigate the electronic and optical properties of self-assembled InN/GaN quantum dots [1]. The one-particle states of the low-dimensional heterostructures are provided by a tight-binding model that fully includes the wurtzite crystal structure on an atomistic level. Optical dipole and Coulomb matrix elements are calculated from these one-particle wave functions and serve as an input for full configuration interaction calculations. We present multi-exciton emission spectra and discuss in detail how Coulomb correlations and oscillator strengths are changed by the piezoelectric fields present in the structure. Vanishing exciton and biexciton ground state emission for small lens-shaped dots is observed.

[1] N.Baer, S. Schulz, S. Schumacher, P. Gartner, G. Czycholl, and F. Jahnke, Appl. Phys. Lett. 87 (2005).