BAND NONPARABOLICITY AND 3-DIMENSIONAL ASPECTS IN QUANTUM DOTS ON INSB

Quantum dots with high lateral quantization energies are created on InSb by means of a perforated Schottky gate. With a gate voltage the lateral quantization energies can be tuned and approach values up to homega0BAR almost-equal-to 25 meV, which is comparable to the subband separations connected with the vertical motion in the corresponding quasi-two-dimensional electron system. By far-infrared spectroscopy, we observe the two fundamental modes omega+/- in a magnetic field and verify the predicted polarization selection rules. The measured transition energies are described by employing a realistic three-dimensional model potential and taking into account the conduction band nonparabolicity of InSb and the resulting coupling of the vertical subbands.