Subband structure of strained-layer CdTe/ZnTe superlattices: A reexamination

Abstract

With recent new values of the CdTe deformation potentials, we present a reexamination of the combined effects of band offsets and lattice mismatch on the subband structure of strained-layer CdTe/ZnTe superlattices. It is shown that the subband structure of these superlattices is very sensitive to the strain parameters. The value \ensuremath{\Delta}${\mathit{E}}_{\mathit{v}}$=55\ifmmode\pm\else\textpm\fi{}40 meV is obtained for the zero-strain valence-band offset and a relation between the CdTe (${\mathit{N}}_{1}$) and ZnTe (${\mathit{N}}_{2}$) monolayer numbers of the strained-layer superlattice (CdTe${)}_{\mathit{N}1}$/(ZnTe${)}_{\mathit{N}2}$ giving rise to a degenerate band gap [E(C1H1)=E(C1L1)] is proposed, ${\mathit{N}}_{1}$\ifmmode\times\else\texttimes\fi{}${\mathit{N}}_{2}$\ensuremath{\simeq}30. For ${\mathit{N}}_{1}$\ifmmode\times\else\texttimes\fi{}${\mathit{N}}_{2}$30, the band gap is E(C1H1), and the superlattice has a type-I configuration; for ${\mathit{N}}_{1}$\ifmmode\times\else\texttimes\fi{}${\mathit{N}}_{2}$>30, the band gap is E(C1L1), and the superlattice has a type-II configuration.