Light absorption related to hole transitions in quantum dots and impurity centers in quantum wells under external excitation

Optical absorption is studied in p-doped GaAs/AlGaAs quantum wells at lattice temperatures 4.2–300 K. Features in the absorption spectrum are associated to hole transitions from ground impurity level to resonant impurity states and subbands. Absorption modulation related to hole redistribution between impurity and subband states is studied. Spectra of intraband absorption are studied in Ge/Si quantum dots in equilibrium and under interband optical excitation. Filling the excited states with nonequilibrium holes leads to arising the additional peak in absorption spectrum related to hole transitions from the excited state.