Properties of two-dimensional electron gas containing self-organized quantum antidots

A nonuniform two-dimensional electron gas in a heterojunction with inserted self-organized electrically inactive dots (acting as antidots) has been fabricated by molecular-beam epitaxy of AlGaAs/AlInAs/GaAs layer sequences. Transport measurements give the ratio of the transport mobility to the quantum mobility less than four, which suggests that the dominant scattering at low magnetic fields is the short-range scattering from the lateral potential of the antidots. Far-infrared cyclotron resonance (CR) spectra show an absorption mode as narrow as 0.5 cm−1 at high magnetic fields associated with the high-mobility electron gas formed between the antidot islands and confined in the lateral directions. The confinement energy of 14 cm−1 is derived from the CR spectra.