Effective mass in remotely doped Ge quantum wells

We report on the dependence of the effective masses on hole density in remotely doped strained Ge layers on relaxed Si0.3Ge0.7 buffers with sheet densities from 2.9×1011 cm−2 to 1.9×1012 cm−2. The masses have been determined using temperature dependent Shubnikov–de Haas oscillations. No noticeable dependence of the mass on the magnetic field has been found. The extrapolated Γ point effective mass has been found to be 0.080 times the free electron mass. From the measured data the variation of the mass with kinetic energy and the shape of the topmost heavy hole subband have been calculated. The results are in good agreement with theoretical predictions.