Scientific Reports (Mar 2023)

BSTS synthesis guided by CALPHAD approach for phase equilibria and process optimization

  • Husain F. Alnaser,
  • Taylor D. Sparks

DOI
https://doi.org/10.1038/s41598-023-30976-3
Journal volume & issue
Vol. 13, no. 1
pp. 1 – 9

Abstract

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Abstract This work presents a new method for processing single-crystal semiconductors designed by a computational method to lower the process temperature. This research study is based on a CALPHAD approach (ThermoCalc) to theoretically design processing parameters by utilizing theoretical phase diagrams. The targeted material composition consists of Bi–Se2–Te–Sb (BSTS). The semiconductor alloy contains three phases, hexagonal, rhombohedral-1, and rhombohedral-2 crystal structures, that are presented in the phase field of the theoretical pseudo-binary phase diagram. The semiconductor is also evaluated by applying Hume–Rothery rules along with the CALPHAD approach. Thermodynamic modelling suggests that single-crystals of BSTS can be grown at significantly lower temperatures and this is experimentally validated by low-temperature growth of single crystalline samples followed by exfoliation, compositional analysis, and diffraction.