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Graded index separate confinement heterostructures (GRIN-SCH) for microgun blue-green laser were grown by MOVPE. A first study was carried out using selenium hydride, dimethyl cadmium and two dimethylzine adducts as Se, Cd and Zn precursor respectively. This combination leads to intense prereactions and poor layer morphology. To limit this problem we have then used the tetrahydrothiophene:dimethylcadmium adduct. We have first investigated the quality of thick ZnCdSe layers grown using this adduct. GRIN-SCH structures grown using the two cadmium metalorganics were studied using photoluminescence and optical pumping experiments. Stimulated emission was observed for the two kind of samples.

ZnSe/ZnTe strained-layer short period superlattices have been grown by MOVPE. Using well adapted buffer layers, we could tune the internal built-in strain of the individual layers. We studied both free standing superlattices and strained-layer superlattices lattice matched to ZnTe. We observe that the tuning of the valence band offset by the internal strain can produce a switching of the superlattice band gap from type II e1hh1 to type I e11h1. Photoreflectance investigations enabled us to measure excited state transitions allowing us to obtain the strain free valence band offset with considerable accuracy.