Phase Equilibria in the Tl2Te–SiTe2 and Tl2SiTe3–Сd(Hg)Te Systems

Component interaction in the Tl2Te – SiTe2 and Tl2SiTe3 – Cd(Hg)Te systems was investigated by X-ray diffraction (XRD), differential thermal analysis (DTA), and scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS) methods. The formation of four new ternary tellurides Tl18SiTe11, Tl4SiTe4, Tl2SiTe3, and Tl2Si2Te5, was found in the Tl2Te – SiTe2 system. The Tl18SiTe11 and Tl2SiTe3 compounds are formed congruently at 778 and 618 K, and Tl4SiTe4 and Tl2Si2Te5 form incongruently at 546 and 584 K, respectively. Quaternary compounds Tl2CdSiTe4 and Tl2HgSiTe4 that form in the Tl2SiTe3 – Cd(Hg)Te systems crystallize in the tetragonal space group I–42m аnd melt incongruently at 826 and 738 K, respectively. Each compound has a homogeneity region up to 5 mol.% from the Tl2SiTe3 side at 520 K.