A Metastable Alloy (Sn$_{1-x}$Ca$_{x}$)S: Growth and Characterization

ORAL

Abstract

Two sulfide systems with different crystal structures SnS (orthorhombic) and CaS (rocksalt) were deposited by pulsed laser deposition to form metastable alloys of varying composition (Sn$_{1-x}$Ca$_{x}$S). The film composition was controlled using separate SnS$_{2}$ and CaS targets: a) a layering technique using 2 different targets and b) using a single target of a mixture of the two systems and varying $T_{sub}$ to evaporate the more volatile cation Sn. The alloyed films' optical and structural properties were analyzed as a function of composition by optical spectroscopy and grazing incidence x-ray diffraction (GIXRD) respectively. Film stoichiometry was determined by electron probe microanalysis (EPMA). EPMA results indicated that, for Sn$_{1-x}$Ca$_{x}$S$_{y}$ layered films, the cation ratio was as expected, allowing for tuning of $x$; however, films were severely sulfur deficient. DFT calculations of the alloy predict a structural transition at $x $\textgreater 0.18; however, GIXRD indicates films are still predominantly orthorhombic for $x =$ 0.25.

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Authors

  • Bethany Matthews

    Department of Physics, Oregon State University, Corvallis OR 97331

  • James Haggerty

    Department of Physics, Oregon State University, Corvallis OR 97331, Oregon State University

  • Bethany Mathews

    International Centre for Theoretical Sciences, Tata Institute of Fundamental Research, Bangalore, India, Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Potsdam-Golm, Germany, Univ of Idaho, Washington State University, University of California Berkeley, University of British Columbia, Max Planck Institute for Solid State Research and Ecole Polytechnique F\'ed\'erale de Lausanne, Max Planck Institute for Solid State Research, University of British Columbia and Max Planck Institute for Solid State Research, Physikalisches Institut, Ruprecht-Karls-Universitaet Heidelberg, Univ of Oregon, Whitman College, The University of British Columbia, Durham University, Universit\"at Freiburg, Institute for Nuclear Theory, University of Washington, National Renewable Energy Laboratory, Golden, CO 80401, Los Alamos National Laboratory, Oregon State University

  • Janet Tate

    Department of Physics, Oregon State University, Corvallis OR 97331, Oregon State University, Department of Physics, Oregon State University