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HL: Halbleiterphysik

HL 36: Quantenpunkte und -dr
ähte: Optische Eigenschaften I

HL 36.12: Vortrag

Donnerstag, 11. März 2004, 13:00–13:15, H17

Time resolved spectroscopy of annealed InAs/GaAs self-assembled quantum dots — •Cedric Bardot¹, M. Schwab¹, M. Bayer¹, D. Reuter², and A. D. Wieck² — ¹Experimentelle Physik II, Otto-Hahn Strasse 4, 44221 Dortmund, Germany — ²Angewandte Festkoerperphysik, Ruhr-Universitaet Bochum, Universitaetsstr. 150, 44780 Bochum, Germany

Understanding the optical properties of semiconductor quantum dots is very important due to their high potential interest in pure optical applications and for quantum computing science as well. Despite many years of intense study several questions are still debated. Existence of a phonon bottleneck that would slow down carrier relaxation is still unclear for instance. Spin relaxation dynamics also needs to be clarified to understand fully the radiative process of excitons on nanosecond scale.

Subjecting InAs/GaAs quantum dot samples to post-growth rapid thermal anneals makes it possible to vary the dimension and the confinement potential of quantum dots and consequently their electronic structure. The influence of this one on optical properties can then be analysed.

In this talk we report on measurements of the rise time and radiative lifetime of photo-excited carriers in InAs/GaAs quantum dots for a series of high quality annealed samples. Dependence of these two important quantities with experimental parameters such as temperature, excitation energy, excitation density and polarization of light is presented and interpreted.