Effect of the degree of disorder on electronic and optical properties in random superlattices

摘要

A threehyphen;dimensional tighthyphen;binding calculation is developed and used to study disorder effects in a realistic random superlattice. With increasing disorder, a tendency of possible indirectndash;direct bandhyphen;gap transition is suggested. Direct evidence of mobility edges between localized and extended states in threehyphen;dimensional random systems is given. As system disorder increases, the optical absorption intensities increase dramatically from five to fortyhyphen;five times stronger than the ordered (GaAs)1/(AlAs)1superlattice. It is believed that the degree of disorder significantly affects electronic and optical properties of GaAs/AlAs random superlattices.