Non-equilibrium Phases Formed in Cu–In–Se–Te System Synthesized by Melt-Quench Method

Non-equilibrium phases formed in melt-quenched CuIn(SexTe1−x)2 system, where x = 0.1, 0.2, 0.4, 0.5, 0.6, 0.8 and 0.9, have been studied using Rietveld refinement of the crystal structure and Raman spectroscopy. Results of structure refinement have showed that all the samples, except the CuIn(Se0.1Te0.9)2, are heterogeneous. All the observed non-equilibrium phases are quaternary system and are found to have chalcopyrite structure (I4¯2d\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ I\bar{4}2d $$\end{document}), in accordance with the CuInTe2–CuInSe2 phase diagram. The lattice constants deduced from the refinement have showed linear variation with Se content. A detailed analysis of the characteristic A1 modes present in the Raman spectrum of individual sample has corroborated the results obtained from the structure analysis. The position of A1 mode of individual phase is found to vary linearly with Se content, which suggests that CuIn(SexTe1−x)2 system exhibits single-mode behaviour.