Exciton spectra of semiconductor clusters

Abstract

The band gaps and exciton energies of CdS and GaP clusters are calculated for the first time using pseudopotentials. The calculated exciton energies of CdS over a wide range of cluster sizes are in excellent agreement with experiment. Furthermore, the exciton states of clusters with zinc-blende and hexagonal lattices are similar in large clusters, but differ dramatically in small clusters. Finally, the spectra of small GaP clusters shift to red, instead of to the blue, with decreasing cluster size. These effects provide novel ways of tuning the optical properties of clusters.