Giant quantum-confined Pockels effect in type-II heterostructures

The in-plane optical anisotropy of ZnSe/BeTe multi-layered heterostructures has been studied by analyzing the linear polarization of the spatially ind irect photoluminescence. A pronounced quantum-confined Pockels effect is re ported in ZnSe/BeTe double-barrier structures. A tight-binding model is pro posed which consistently interprets the experimental findings and suggests a new mechanism of the Pockels effect realized in type-II heterostructures. The model takes into account that the ZnSe/BeTe heterosystem exhibits a ty pe-II band alignment with large band offsets and that in the zinc-blende la ttice the chemical bonds are oriented in [1 1 1]-like directions and, when shifted along the [0 0 1] principal axis, alternatively change their orient ation in the (0 0 1) plane from [1 (1) over bar 0] to [1 1 0] and vice vers a. (C) 2000 Elsevier Science B.V. All rights reserved.