SYNTHESIS AND RAMAN CHARACTERIZATION OF SOME SELENIUM DEFECT CHALCOPYRITE ALLOYS

We have synthesized by CVT techniques some ternary and quaternary sele nide compounds of the defect chalcopyrite families ZnxCd1-xGa2Se4, Znx Cd1-xIn2Se4, ZnGaxIn2-xSe4 and CdGaxIn2-xSe4. These systems have been investigated to determine the effect of the cation mixing on the Raman spectra. The Zn-Cd mixing in isomorphous selenium compounds confirms the results on mode behaviour found for corresponding sulphides, while in non-isomorphous compounds no clear trend is manifested. The In-Ga substitution on the complete range of the solid solution suggests a mi xed one- and two-modes behaviour.