OPTIMIZATION AND OPTICAL STUDIES OF ZNCDSE-ZNSE HETEROSTRUCTURES GROWN BY MOVPE

Graded index-separate confinement heterostructures (GRIN-SCH) based on ZnCdSe and ZnSe wide band gap semiconductors have been grown by low p ressure MOVPE on (100) GaAs substrates. First, we have paid attention to the growth of thick ZnCdSe layers. A first study is carried out usi ng selenium hydride, dimethyl cadmium and two dimethylzinc adducts as Se, Cd and Zn precursor respectively. This combination leads to intens e prereactions and poor layer morphology. To limit this problem we hav e then used the tetrahydrothiophene:dimethylcadmium adduct. GRIN-SCH s tructures grown using the two Cd metalorganics are studied using photo luminescence. We have made a detailed study on the influence of the te mperature on the carrier trapping and detrapping in the structures.