Ground-state energy of an exciton in a quantum-dot superlattice grown on a terraced substrate

For adequate material combinations, the growth of a fractional monolayer on a terraced substrate is expected to form a two-dimensional superlattice of flat square quantum boxes. We present a variational calculation of the ground-state energy of an exciton in such a structure. The treatment is performed within a two-band effective mass approximation. Numerical results are presented for the heavy-hole exciton in an InAs/InP quantum-dot superlattice, giving the exciton ground-state energy, the contribution of the electron-hole interaction to this energy, and the extension of the exciton wave function in the superlattice plane. These calculations indicate that the exciton ground-state energy varies considerably with the quantum-dot superlattice parameters. A fair agreement is found with the few available experimental results. © 1996 The American Physical Society.