SINGLE-PARTICLE EXCITATIONS IN QUASI-ZERO-DIMENSIONAL AND QUASI-ONE-DIMENSIONAL ELECTRON-SYSTEMS

Resonant inelastic light scattering is used to probe electronic excitations in shallow etched GaAs/AlGaAs quantum dots and wires. In both types of structures, intersubband excitations are observed in depolarized scattering geometries. They show significant blueshift with decreasing confinement length. In dot structures these transitions appear as dispersionless, whereas in wires they show strong broadening and an intensity dip at the energetic center of the excitation with increasing wave vector parallel to the wires, as expected for single-particle excitations. Their line shape correlates with the linear wave vector dispersion of additionally observed intrasubband excitations. © 1994 The American Physical Society.