CPM Seminar

State-Resolved Exciton Dynamics in Quantum dots

Patanjali Kambhampati

Department of Chemistry
McGill University

The semiconductor quantum dot is one of the canonical systems in nanoscience. Whereas the nanometer size of these materials is obvious, the richer and more meaningful issue is the presence of quantum confinement effects conferred by virtue of size. One may qualitatively describe quantum dot electronic structure like the textbook particle in a sphere. However, this simple picture misses the vast majority of the processes which ultimately control the functionality of the quantum dot. Our goal is to obtain a detailed picture of the rich inner workings of the quantum dot.

We introduce a mixed time/frequency domain ultrafast spectroscopic approach which we denote State-Resolved Exciton Dynamics. We have applied this approach to resolve several long standing issues central to quantum dot science: 1) hot exciton relaxation dynamics, 2) optical gain, 3) multiexcitons � creation of an artificial periodic table, 4) electron-phonon interactions and quantizing piezoelectricity. The power of this approach is reflected by our ability to predict aspects of unrelated experiments, e.g. single dot blinking and multiple exciton generation. We conclude with femtosecond and single dot spectroscopy of newer core/barrier/shell materials.

For more information, please visit: http://kambhampati-group.mcgill.ca/