  The effects of chemical disorder on the electronic and optical properties of
semiconductor alloy multilayers are studied based on the tight-binding theory
and single-site coherent potential approximation. Due to the quantum
confinement of the system, the electronic spectrum breaks into a set of
subbands and the electronic density of states and hence the optical absorption
spectrum become layer-dependent. We find that, the values of absorption depend
on the alloy concentration, the strength of disorder, and the layer number. The
absorption spectrum in all layers is broadened because of the influence of
disorder and in the case of strong disorder regime, two optical absorption
bands appear. In the process of absorption, most of the photon energy is
absorbed by the interior layers of the system. The results may be useful for
the development of optoelectronic nanodevices.
