Dresden 2017 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 63: Poster: Quantum Dots and Optics
HL 63.3: Poster
Mittwoch, 22. März 2017, 15:00–19:00, P1A
On the phonon assisted absorption in Cu2O — •Florian Schöne and Heinrich Stolz — Universität Rostock, Institut für Physik
A common approach to describe the shape of the excitonic absorption close to the band gap is based on the formalisms introduced by Elliott1 60 years ago utilising the transition probabilities between electronic bands. We follow his ansatz for indirect transitions via second order perturbation theory which can be visualised as an excitation into a virtual intermediate state and the subsequent relaxation to the final state through the emission of a phonon. However, instead of assuming the intermediate states to be pure band states, for materials with large exciton binding energies it is necessary to use the corresponding exciton states. This leads to the invalidity of the commonly assumed square root dependence of the absorption2. Applying our theory to the indirect absorption of the yellow exciton states in Cu2O we find the 1S blue exciton states to be the dominant intermediate states. To describe the experimental observed line shape3 it is furthermore necessary to assume a momentum dependent deformation potential for the Γ3− phonon.
[1] Elliott R.J., Phys. Rev. 108, 1384 (1957)
[2] Kuper C. G., Whitfield G. D., "Polarons and Excitons." Oliver and Boyd, London (1963)
[3] Naka N., Satoshi H., Teruya I., Jpn. J. Appl. Phys. 44 5096 (2005)