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Valence subbands and acceptor levels in p-type GaAs-AlxGa1-xAs superlattices

Raman scattering and far-infrared (reflectance and transmission) spectra are measured to study valence subband transitions, transitions between the ground and (s-like) excited states of Be acceptors, and acceptor binding energies in p-type modulation-doped GaAs-AlxGa1-xAs superlattices with narrow (40 AA) wells. The results show carrier confinement effects and the splitting of the acceptor levels in quantum well structures. The observed transition energies agree with calculations for valence subbands, acceptor levels and binding energies, which depend strongly on well width.