Piezoelectric-field effects on transition energies, oscillator strengths, and level widths in (111)B-grown (In,Ga)As/GaAs multiple quantum wells

We report a spectroscopic study of high-quality piezoelectric (PZ) (111)B GaAs/(In,Ga)As strained multiple quantum wells. Normally forbidden Δn≠0 transitions (E1HH2, E1HH3, E2HH1) are observed strongly due to the asymmetric well profile induced by the PZ field. Applying a bias to oppose the PZ field reduces the quantum-confined Stark shifts and weakens the Δn≠0 transitions. At high bias, corresponding to flat band in the well, strong lifetime broadening is observed. Good agreement between theory and experiment is found, but only by using a value for the PZ constant ∼30% smaller than the commonly accepted value.