Interface properties and in-plane linear photoluminescence polarization in highly excited type-II ZnSe/BeTe heterostructures with equivalent and nonequivalent interfaces

Properties of interfaces with no-common atom in type-II ZnSe/BeTe heterostructures are studied with polarization spectroscopy. Structures with four possible configurations of normal and inverted interfaces have been investigated. Radiative recombination and its polarization anisotropy have been found to depend crucially on the interface configuration and excitation power. The comparison of interfaces formed by the growth on anion (Se, Te) and cation (Zn, Be) terminated layers has shown that the latter demonstrate a significantly higher nonradiative recombination rate. In agreement with the quantum well (QW) symmetry, the photoluminescence (PL) of the structures with nonequivalent normal and inverted interfaces is highly linearly polarized both at low and high excitation densities. Unexpectedly, a similarly strong PL polarization has been found for structures with equivalent interfaces up to carrier densities of ${10}^{12} {\mathrm{cm}}^{\mathrm{-2}}$ per QW. The polarization is explained by a built-in electric field, it decreases with increasing carrier concentration due to screening of the electric field. Finally, we have found that the PL polarization degree at interfaces with Be–Se and Zn–Te bonds amounts to about 50% and $\text{≈70\%,}$ respectively.