【International Papers】Gas sensing performance of α-, α/β-, and β-Ga₂O₃ polymorphs

      Researchers from the University of the Witwatersrand have published a dissertation titled "Gas sensing performance of α-, α/β-, and β-Ga₂O₃ polymorphs" in Materials Research Bulletin.

Abstract

      This paper reports the detection of SO₂, NH₃, and CO gases using Ga₂O₃ polymorphs. The α-Ga₂O₃, α/β-Ga₂O₃, and β-Ga₂O₃ sensing materials were prepared using the hydrothermal method, followed by calcination at different temperatures ranging from 550 °C to 950 °C. The gas sensing properties were measured and analyzed based on the polymorphism-induced physicochemical properties of the sensing materials. Different Ga₂O₃ polymorphs showed distinct sensing properties, and factors contributing to this preferential gas detection behavior are discussed in detail. The proposed gas sensing mechanisms were discussed. Notably, the gas sensing performance of the α/β-Ga₂O₃-based sensor is reported here for the first time.

Highlights

      · The α-, β-, and α/β-Ga₂O₃ nanorod/nanowire structures were prepared by a hybrid hydrothermal and calcination process.

      · The phase transformation between α- and β-Ga₂O₃ was controlled by varying the calcination temperature.

      · The β-Ga₂O₃ phase showed a response of 1.18 and lowest detectable limit of 2.3 ppm toward CO.

      · The phase-dependent gas sensing properties were attributed to differences in the structural characteristics of the materials.