Strain Effects on Bound Exciton Luminescence in Epitaxial GaAs Studied Using a Wafer Bending Technique

Abstract

Wafer bending was used to achieve externally controlled biaxial and uniaxial strains in high purity GaAs epilayers grown by MBE to study strain effects on bound exciton luminescence. Behavior of the energy levels under [001] and [110] strains confirms the validity of the crystal-field scheme for the acceptor bound excitons. The ratio of the deformation potentials d/b = 2.4 ± 0.1 was determined from the best fit to the experiment. Distinct anti-crossing under uniaxial stress of the two lowest energy levels was observed for the donor bound excitons. Component 3 of donor bound exciton luminescence, previously assigned to the state J = 1/2, splits under stress into a doublet. The complex behavior of the energy levels under stress may require a revision of the existing models of the donor bound exciton in GaAs.