Confinement of excitons in quantum dots

G.T. Einevoll, Institutt for Fysikk, Norges Teknisk Høgskole, Universitetet i Trondheim, 7034 Trondheim, Norway

Physical Review B 45, 3410-3417 (1992)

Abstract

A theoretical study of exciton confinement in small CdS and ZnS quantum dots is reported. In our calculational scheme the hole is described by an effective bond-orbital model which accounts for the valence-band degeneracy in bulk semiconductors. The electron is described with a single-band effective-mass approximation. The confining quantum dot potentials for the hole and electron are modelled as spherically symmetric potential wells with finite barrier heights. The electron-hole Coulomb attraction is included and exciton energies are obtained variationally in an iterative Hartree scheme. Exciton energies for dot diameters in the range 10-80 Å are calculated and compared with experimental data and other theoretical results.