Peak position of the intersubband absorption spectrum of quantum wells with controlled electron concentrations

We investigated the influence of electron concentration N-s on the peak pos ition energy of intersubband absorption spectra in single modulation doped GaAs-Al0.4Ga0.6As quantum well structures of different thicknesses and dopi ng profiles. We found experimentally very small shifts of peak position as a function of N-s. Also the sign of the energy shift is dependent on the we ll thickness. Findings were well explained by a compensation between depola rization shift and shift due to static Coulomb interaction of the electrons . The effect of the well width and the doping profile on the peak shift wer e also discussed.