Berlin 2008 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 16: Quantum dots and wires: Optical properties I

HL 16.6: Vortrag

Montag, 25. Februar 2008, 15:15–15:30, ER 164

Excitonic dynamics in II-VI quantum rods — •Alexander W. Achtstein, Björn Möller, Andrew Ebbens, and Ulrike Woggon — Institute of Physics, Technical University of Dortmund, D-44221 Dortmund, Germany

Highly luminescent colloidal II-VI semiconductor nanorods of large aspect ratio and diameters within the semiconductors exciton Bohr radius are studied by spatially and time-resolved spectroscopy. The influence of rod thickness variation for constant rod aspect ratio is investigated with respect to excitonic confinement and exciton dynamics. High resolution PL measurements show the existence of an excitonic fine structure inside the rods. Possible reasons for its appearance will be discussed. Temperature dependent cw and time resolved PL measurements are conducted to study the influence of this 1D confinement on the electronic structure of these nanowires. Ultrafast dynamics shows, that deexcitation is mainly provided by two competing relaxation channels. The fast one in the 100ps regime can be attributed to nonradiative processes, whereas the slow one, with time constants of about 1ns, can be assigned to the radiative lifetime, which is much longer than the radiative lifetime for bulk II-VI materials.