Strain and crystallographic orientation effects on interband optical matrix elements and band gaps of [11l ]-oriented III-V epilayers

We report a derivation of the 4×4 Luttinger valence band and Bir–Pikus strain Hamiltonians valid for any [11l]-oriented epilayers. It is shown that epitaxial layers grown on substrates oriented in certain of the [11l] directions exhibit anisotropic optical transition matrix elements. This anisotropy is predicted to have its maximum for the (110) surface. For pseudomorphic epitaxial layers, calculations indicate that the zone center band gap of these structures is changed due to the effects of strain, with the largest changes occurring for those structures grown on the (111) surface.