Orientation of chemical bonds at type-II heterointerfaces probed by polarized optical spectroscopy

Time-resolved and cw photoluminescence (PL) spectra are studied in type-II ZnSe/BeTe multiple quantum wells. Samples with nonequivalent interfaces exhibit a strong in-plane linear polarization of the PL along a $〈110〉$ axis. The polarization is stable with respect to an increase in the excitation intensity by many orders of magnitude, to a raising of the temperature up to 300 K and not influenced by applied electric or magnetic fields. The experimental data are discussed in the framework of a tight-binding model taking into account a type-II band alignment and lack of common atom in the ZnSe/BeTe heterosystem.