Energy-dependant cyclotron mass in InAs/AlSb quantum wells

The influence of conduction band non-parabolicity on the cyclotron resonance of a two-dimensional electron system in InAs quantum wells is investigated. We demonstrate that the experimentally determined dependence of the cyclotron mass on the carrier density in the well can be excellently described using a two-band k.p model. In contrast to previously studied systems our experimental results allow us to deduce quantitatively the quantization energy of the first electrical subband for wells of different width.