Quasi-one-dimensional excitons in lateral surface-induced superlattices

Abstract

We study the effects of an electrostatic potential designed to induce a lateral periodic modulation in a quantum well. The resulting superlattice, for small periods, is a system where quasi-one-dimensional excitons can tunnel from one effective potential well to the next and exhibit a unique center-of-mass folded dispersion which should be accessible to photoluminescence experiments. An effective-mass envelope-function approach is used to estimate resulting excitonic minibands, binding energies, and absorption coefficients for the ground and first few excited states of heavy-hole excitons. For strong electrostatic confinement, this configuration strongly polarizes the excitons, resembling a type-II superlattice where electrons and holes are spatially separated in different potential wells. A competition between quantum structural confinement and Coulomb interactions is evident in the exciton features.