Strongly polarized bound exciton luminescence from GaAs grown by molecular beam epitaxy

Abstract
We report strongly polarized luminescence spectra in the 1.504–1.511-eV spectral region in GaAs layers grown by molecular beam epitaxy. Up to 50 individual features are observed in very well resolved spectra. The sharp lines are attributed to bound exciton recombination at defect pairs preferentially oriented parallel to one of the 〈110〉 directions in the (001) growth plane. The preferential orientation occurs because of the inequivalence during planar growth of the [110] and [1̄10] directions in the zincblende lattice.