Acceptor Raman scattering in GaAs-AlxGa1−xAs quantum-well structures

摘要

We report resonant Raman scattering from Be acceptors in GaAs-AlxGa1-xAs quantum well structures, grown by molecular beam epitaxy. Center- and edge-doped samples with well widths in the range 70-165 A were investigated as a function of temperature and uniaxial stress. The data show confinement-induced shifts and splittings of the lowest-lying acceptor levels in good agreement with recent calculations, and also excitations that may involve impurity states derived from higher subbands. The stress dependence of the spectra reveals coupling of the lowest acceptor transition to transverse acoustic phonons. Confinement-split lines exhibit a not fully understood intensity exchange with increasing temperature.