Effects of quantum confinement and strain in Zn1-xCdxSe/ZnSe strained-layer superlattices

The effects of strain and quantum confinement in Zn1-xCdxSe/ZnSe strained-layer superlattices grown by molecular beam epitaxy on the GaAs(100) substrates were studied using photoluminescence (PL) at 4.4 K. The sample with 30 periods and total thickness of 3600 AA was directly grown on the substrate without a buffer layer. The PL spectrum shows a single peak that is attributed to the free excitons between the lowest electron subband and ground heavy-hole subband of the Zn1-xCdxSe wells. The blue shifts of the excitonic peaks in the PL spectra induced by the effects of strain and quantum confinements were calculated on the basis of deformation potential theory and Bastard's method, respectively. In addition, the temperature dependence of the PL features of the sample was studied both theoretically and experimentally in detail. The experimental results coincide with the theoretical predictions very well. (author)