Raman Spectroscopy on Tunable GaAs Double Quantum Wells and Wires
Dr Annelene Dethlefsen
Centre for Atom Optics and Ultrafast Spectroscopy
Swinburne University of Technology
Friday, 23 November 2007, 2.00pm, EN214, Engineering Building, Hawthorn.
Low-dimensional electron systems play an important role in
technological applications in the field of microelecronics as
well as in basic research on quantum-mechanical systems.
A great amount of fundamental research was performed on two
dimensional electron systems. Here the most famous experiment
was certainly the discovery of the integer Quantum Hall effect by
Klaus von Klitzing in 1980.
After an introduction on semiconductor fabrication techniques I will
show the investigation of electronic excitations in GaAs-AlxGa1-xAs
double-layered quantum wire arrays with strong tunneling coupling
by resonant inelastic light scattering. By applying an external
electric field, the one-dimensional electron density and the symmetry
of the double quantum-well (DQW) structure can be changed at the
same time. Confined optical and acoustic intersubband plasmons can
be identified. Due to the tunneling coupling, the energies of the
acoustic intersubband plasmons exhibit a minimum for a symmetric DQW
potential, whereas the energies of the confined optical plasmons are
dominated by the total carrier density, and are nearly insensitive to
symmetry of the potential.
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