Experimental evidence of the exciton centre-of-mass quantization in Zn1−x Cd x Se/ZnSe multiple quantum wells

We report the evidence of exciton-polariton centre-of-mass quantization in II–VI quantum wells consisting of ternary alloy. Absorption and photoluminescence studies on Zn0.89Cd0.11Se/ZnSe quantum wells, covering the intermediate region between two- and three-dimensional exciton behaviour, exhibit distinct optical resonances in the high-energy tail of the free-exciton structure. We reproduce the well width dependence of the centre-of-mass states by modeling the optical response of the QWs with a thin-slab variational wave function, which takes into account non-adiabatic terms.