FILLING-FACTOR-DEPENDENT CYCLOTRON-RESONANCE IN GAINAS ALINAS MODULATION-DOPED SINGLE QUANTUM-WELLS

The line shape of cyclotron resonance (CR) absorption is investigated for a two-dimensional electron gas (2DEG) in modulation-doped GaInAs/A lInAs narrow SQW structures. CR absorption is measured as functions of far infrared (FIR) frequency, temperature, and carrier concentration. At low temperature and short FIR wavelengths, a well-defined filling- factor-dependent quantum oscillation structure is obtained for samples with high 2DEG concentrations, exhibiting clear maxima and minima and a phase change point at the top of the CR peak. The modulated scatter ing is attributed to short-range scatterers originating mainly from al loy scattering. A part of the contribution comes from ionized impurity scattering. The analysis of the temperature dependence of the CR line width and Hall mobility gives additional support to this argument. An electron effective mass as high as 0.063m0 in In0.53 Ga0.47As is obse rved due to the non-parabolicity effect.