Unconventional Route to High-Pressure and -Temperature Synthesis of GeSn Solid Solutions

George Serghiou, Nicholas Odling, Hans J. Reichmann, Kristina Spektor, Wilson A. Crichton, Gaston Garbarino, Mohamed Mezouar, Anna Pakhomova

Research output: Contribution to journalArticlepeer-review

Abstract

Ge and Sn are unreactive at ambient conditions. Their significant promise for optoelectronic applications is thus largely confined to thin film investigations. We sought to remove barriers to reactivity here by accessing a unique pressure, 10 GPa, where the two elements can adopt the same crystal structure (tetragonal, I41/amd) and exhibit compatible atomic radii. The route to
GeSn solid solution, however, even under these directed conditions, is different. Reaction upon heating at 10 GPa occurs between unlike crystal structures (Ge, Fd3m and Sn, I4/mmm), which also have highly incompatible atomic radii. They should not react, but they do. A reconstructive transformation of I4/mmm into the I41/amd solid solution then follows. The new tetragonal GeSn solid solution (I41/amd a = 5.280(1) Å, c = 2.915(1) Å, Z = 4 at 9.9 GPa and 298 K) also constitutes the structural and electronic bridge between 4-fold and newly prepared 8-fold coordinated alloy cubic symmetries. Furthermore, using this high-pressure route, bulk cubic diamond-structured GeSn alloys can now be obtained at ambient pressure. The findings here remove confining conventional
criteria on routes to synthesis. This opens innovative avenues to advanced materials development.
Original languageEnglish
Pages (from-to)7920-7924
Number of pages5
JournalJournal of the American Chemical Society
Volume143
Issue number21
DOIs
Publication statusPublished - 19 May 2021

Keywords

  • new materials
  • synthesis
  • alloys
  • solid solutions
  • pressure and temperature
  • angle dispersive X-ray diffraction

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