Abstract
he longitudinal optical (LO) and transverse optical (TO) phonons of zincblende Zn1–x–yMgyBexSe with x,y~0.15 are identified by Raman scattering. The Be–Se region exhibits a two-mode behavior similar to that observed with the random Zn1–xBex(Se,Te) systems. This indicates that the percolation picture set for the latter mixed crystals with contrasted bond stiffness extends to Be-based multinaries. Accordingly the low- and high-frequency modes refer to Be–Se bonds within the Be-rich hard-like region and the (Zn,Mg)-rich soft-like one, respectively. Besides, we derive the (x,y) values together with the fraction p of Be atoms in the hard-like region from combined contour modeling of the TO and LO Raman line shapes. We find p~x, as in the ZnBe(Se,Te) references. We deduce that the Be incorporation is random in ZnMgBeSe.