Cyclotron resonance in doped and undoped InAs/AlSb heterostructures with quantum wells

Backward-wave tubes are used to study the spectra of cyclotron resonance in the range of 150-700 GHz in the AlSb/InAs/AlSb heterostructures with quantum wells and with an electron concentration in a two-dimensional electron gas ranging from 2.7 × 10¹¹ to 8 × 10¹² cm ² at 4.2 K. A significant increase in the cyclotron mass (from 0.03m₀ to 0.06m₀) is observed as the electron concentration (and, correspondingly, the Fermi energy) increases, which is typical of semiconductors with a nonparabolic dispersion relation. The results obtained are in satisfactory agreement with theoretical calculations of cyclotron masses at the Fermi level in the context of the simplified Kane model.