Regensburg 2013 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 3: Focus Session: Electron-phonon interaction and ultrafast processes in semiconductors

HL 3.7: Talk

Monday, March 11, 2013, 13:00–13:15, H13

Electron-phonon coupling in colloidal CdSe/CdS core-shell quantum dots — •Steffen Westerkamp, Andrei Schliwa, Amelie Biermann, and Christian Thomsen — Institut für Festkörperphysik, Technische Universität Berlin, Germany

Phonon frequencies and eigenvectors, and their coupling to excited electronic states are calculated for approximately spherical, CdSe/CdS core-shell quantum dots (QD).

The equilibrium atomic positions and phonon modes are obtained using an empirical force model. Electron and hole wavefunctions are calculated using the 8-band-kp envelope function method, thus taking into account band coupling, strain, and piezo/pyroelectric effects. These results are combined to determine the Huang-Rhys-factors thus reflecting the electron-phonon coupling for each phonon mode.

We vary size, core-shell thickness ratio, and the sharpness of the interface of the quantum dots and discuss the impact of interface- and surface-phonons.