Abstract
Spontaneous -type ordering along 〈111〉 can reduce the crystal symmetry in P, splitting the valence-band maximum and introducing optical anisotropy in the interband transition-matrix elements. The growth of lattice-mismatched layers also reduces the symmetry. We present a simple model to describe the combined influence of strain and ordering on the valence-band maximum. We calculate that the valence-subband dispersion and optical-matrix elements are strongly anisotropic over a significant energy range in P quantum wells with coexistent epitaxial strain and [1¯11] chemical ordering, using the simple model to explain the observed results. Comparison with disordered, unstrained quantum wells indicates that a combination of chemical ordering and strain may lead to significantly improved gain characteristics in high-quality P layers.
- Received 28 November 1994
DOI:https://doi.org/10.1103/PhysRevB.51.7566
©1995 American Physical Society