High pressure synthesis in gallium sulphide chalcogenide

Researchers from Universitat Politècnica de València, Universidad de La Laguna, Universidad de Cantabria and the ALBA Synchrotron have published a new work on high pressure chemistry in gallium (III) sulphide chalcogenide. In this work, relevant fingerprints (vibrational and structural) of a pressure-induced paralectric to ferroelectric phase transition are shown. This is the first time when a tetradymite-like (R3m) phase has been synthesized and observed experimentally in gallium-based sequichalcogenides. High pressure X-ray diffraction measurements were carried out at MSPD beamline of ALBA.

Gallium (III) sulphide (Ga2S3) is a compound of sulphur and gallium, that is a semiconductor that has a wide variety of applications in electronics and photonics: nano optoelectronics, photonic chips, electro-catalysis, energy conversion and storage, solar energy devices, gas sensors, laser-radiation detection, second harmonic generation, phase change memories or photocatalytic water splitting systems.

In this work published in Chemistry of Materials,scientists have shown relevant vibrational and structural fingerprints of a pressure-induced paraelectric to ferroelectric R-3m-to-R3m (β’-to-φ) phase transition under decompression on Ga2S3 chalcogenide.

This transition was theoretically predicted in several III−VI B2X3 compounds at high temperature (where B can be aluminium, gallium or indium and X, sulphur, selenium or tellurium). The novelty of this research stems from the synthesis of both phases: β-(R-3m) and α-In2Se3 (R3m)-like structures on Ga2S3 and tuning them via decreasing pressure. Within the III−VI B2X3 compounds, this R-3m-to-R3m (β’-to-φ-Ga2S3) phase transition had been observed experimentally only in the indium (III) selenide (In2Se3)compound, under varying temperature or pressure, to date.

This finding leads the way for designing cheap, nontoxic, nonrare-earth, and abundant element-based devices for second harmonic generation, photocatalytic splitting, ferroelectric, pyroelectric, and piezoelectric applications based on Ga2S3.

Read more on the ALBA website

Image: Samuel Gallego and Catalin Popescu at the MSPD beamline of ALBA.