OPTICAL ANISOTROPY IN [311]-ORIENTED GAAS ALAS SUPERLATTICES/

[311]-oriented GaAs/AlAs superlattices have a monoclinic unit cell and are thus anisotropic in the plane of the superlattice layers. The sup erlattice interfaces have a periodic corrugation along the [<(2)over b ar 33>] in-layer direction in form of macrosteps with a height of 10.2 Angstrom. The effects of the interface corrugation on the optical ani sotropy are investigated in the energy range of the bulk GaAs E(1) and E(1) + Delta(1) using ellipsometry and reflection difference spectros copy. The experimental results are compared to an effective medium cal culation of the optical anisotropy. It is found that the measured anis otropy is considerably smaller than that expected from the interface c orrugations. Reasons for these discrepancies are discussed in the text .