“…Piezoelectric potentials, however, caused by shear strain from the lattice mismatch between InAs and GaAs, tend to elongate the hole in the ͓110͔ direction, and the electron in the ͓110͔ direction. 24 Thus for strongly confined states, shear strain tends to also elongate the exciton in the ͓110͔ direction, since the extent of the exciton wave function is dominated by the small hole. However, as confinement is reduced, shape asymmetry becomes less dominant as the electron and hole states extend into the barrier, and the relative size and elongation of the electron and hole states could potentially lead to an exciton state elongated along ͓110͔, the preferred axis of expansion for the electron.…”