APL Materials (Aug 2018)

Band gap temperature-dependence of close-space sublimation grown Sb2Se3 by photo-reflectance

  • Max Birkett,
  • Wojciech M. Linhart,
  • Jessica Stoner,
  • Laurie J. Phillips,
  • Ken Durose,
  • Jonathan Alaria,
  • Jonathan D. Major,
  • Robert Kudrawiec,
  • Tim D. Veal

DOI
https://doi.org/10.1063/1.5027157
Journal volume & issue
Vol. 6, no. 8
pp. 084901 – 084901-8

Abstract

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The candidate photovoltaic absorber antimony selenide Sb2Se3 has been prepared by the commercially attractive close-space sublimation method. Structure, composition, and morphology are studied by x-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. Large rhubarb-like grains favorable for photovoltaics naturally develop. The temperature-dependence of the direct band gap is determined by photoreflectance between 20 and 320 K and is well described by the Varshni and Bose–Einstein relations, blue-shifting with decreasing temperature from 1.18 to 1.32 eV. The 300 K band gap matches that seen in high quality single-crystal material, while the 0 K gap is consistent with that found in first-principles calculations, further supporting the array of beneficial photovoltaic properties indicated for this material.