Langbein, Wolfgang Werner1; Gislason, Hannes1; Hvam, Jørn Märcher2
1 Department of Micro- and Nanotechnology, Technical University of Denmark2 Department of Photonics Engineering, Technical University of Denmark
The binding energy of excitons and biexcitons and the exciton dephasing in T-shaped GaAs quantum wires is investigated by transient four-wave mixing. The T-shaped structure is fabricated by cleaved-edge overgrowth, and its geometry is engineered to optimize the one-dimensional confinement. In this wire of 6.6 x 24 nm(2) size, we find a one-dimensional confinement of more than 20 meV, an inhomogeneous broadening of 3.4 meV, an exciton binding energy of 12 meV, and a biexciton binding energy of 2.0 meV. A dispersion of the homogeneous linewidth within the inhomogeneous broadening due to phonon-assisted relaxation is observed. The exciton acoustic-phonon-scattering coefficient of 6.1 +/- 0.5 mu eV/K is larger than in comparable quantum-well structures.
Physical Review B (condensed Matter and Materials Physics), 1999, Vol 60, Issue 24, p. 16667-16674