Electronic structure of free-standing (ZnSe)m(ZnS)n(001) strained-layer superlattices
| Autor: | T. S. Marshall, T. M. Wilson |
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| Rok vydání: | 1994 |
| Předmět: | |
| Zdroj: | Physical Review B. 50:15034-15046 |
| ISSN: | 1095-3795 0163-1829 |
| DOI: | 10.1103/physrevb.50.15034 |
| Popis: | The electronic structure of free-standing (ZnSe${)}_{\mathit{m}}$(ZnS${)}_{\mathit{n}}$ (001) strained-layer superlattices is studied through ab initio non-self-consistent factorized linear combination of atomic orbitals calculations, where the nonrelativistic local-density-functional formalism of Slater is used to represent the crystalline potential. The effects of elastic strain on the crystal superlattice structure are determined using the valence force field or Keating model. The heavy- and light-hole states are found to be localized in the ZnSe sublattice, while the lowest conduction state is delocalized all along the structure. The valence-band offset is determined to be large and increases as the strain on the ZnSe sublattice is increased. The conduction-band offset, though, is determined to be near vanishing, independent of the strain. These results suggest that for all degrees of strain there is a strong confinement of the holes in the ZnSe sublattice and a weak confinement of the electrons. This lack of a strong type-I formation accounts for the weak blue luminescence observed in photoluminescence and absorption measurements at room temperature. |
| Databáze: | OpenAIRE |
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