Dresden 2006 – scientific programme

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HL: Halbleiterphysik

HL 7: Quantum dots and wires: Optical properties I

HL 7.10: Talk

Monday, March 27, 2006, 12:30–12:45, POT 151

Excited state emission and carrier dynamics of single InP/GaInP quantum dots — •Matthias Reischle¹, Gareth J. Beirne¹, Robert Roßbach², Michael Jetter², and Peter Michler¹ — ¹5. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany — ²4. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70569 Stuttgart, Germany

InP quantum dots (QDs) are promising candidates for lasers and single photon sources in the visible spectral range. To proceed towards a room temperature operating device first the complex carrier dynamics have to be understood. Therefore we have performed power dependent-, temperature dependent-, and time-resolved measurements on single QDs. Approximately 50% of the dots exhibit a number of additional recombination-lines which emerge at high power-densities and are thought to originate from excited states. In general we have observed up to four distinct excited states from these dots. Furthermore, we have observed a strong correlation between the level spacings and the activation energies obtained from fitting the temperature dependence of the emission intensity using an Arrhenius model. This indicates, that at elevated temperatures carriers can occupy succesively higher excited states and thereby eventually escape from the dot.