By the application of disorder, an indirect–direct band gap transition can be achieved in a random superlattice composed of GaP and AlP monolayers. In all random models studied here, optical absorption intensities are found to be larger than that of the ordered ultrathin‐layer GaP/AlP superlattice. With increasing disorder, a considerable optical enhancement, which is about 44 times stronger than that of the ordered structure with equal composition, is obtained in a proposed random system. These properties suggest that the disordered superlattice offers great potential for application to optical devices. ©1995 American Institute of Physics.