Polymorphism of Ga₂O₃ and the System Ga₂O₃—H₂O

On the ammonolysis of Ga2O3: An XRD, neutron diffraction and XAS investigation of the oxygen-rich part of the system Ga2O3–GaN

“…Under standard conditions b-Ga 2 O 3 is the thermodynamically stable phase in the Ga-O system [25,26]. It crystallizes in the monoclinic crystal system (C2/m).…”

“…(2). However, for temperatures above 870 1C all these modifications transform to the stable b-phase [25,26]. In our experiments, all powder samples were prepared from commercially available Ga 2 O 3 powder (Alfa Aesar, Puratronic) by pre-sintering for 48 h at 1325 1C in air to ensure phase purity of the b-phase and to increase the crystallite size to a level where diffraction line broadening is negligible.…”

Heteroepitaxial growth of ε-Ga2O3 thin films on cubic (111) MgO and (111) yttria-stablized zirconia substrates by mist chemical vapor deposition

“…In 1952, metastable ε-phase Ga 2 O 3 was first synthesized through the thermal decomposition of Ga(NO 3 ) 3 by Roy et al 14) However, it was much later, in 2013, when Playford et al 17) identified the crystal structure of the ε-phase as hexagonal and highly symmetric (space group: P6 3 mc, a = 2.9073 Å, c = 9.2559 Å). Given the fact that this polymorph exhibits the same crystal structure as typical widebandgap materials such as GaN, ZnO, and AlN, ε-Ga 2 O 3 is most attractive for application in wide-bandgap semiconductors.…”

“…13) Ga 2 O 3 appears in five polymorphs, i.e., α-, β-, γ-, δ-, and ε-phases. 14) Among these polymorphs, the monoclinic β-phase is the most stable thermodynamically, and it can be used to develop larger and higher-quality single crystal wafers. 15) In contrast, for the metastable phase, Oda et al 16) presented Schottky barrier diodes of the corundum α-phase Ga 2 O 3 heteroepitaxially grown on sapphire substrates.…”

Supported Ga-oxide Catalyst for Dehydrogenation of Ethane

“…However, the peak intensity of the low transition energy (10373 eV) is higher than that of the high transition energy (10378 eV) 28) . It is known that β-Ga2O3 is the only stable phase 29) and it includes two kinds of Ga, tetrahedral Ga and octahedral Ga, in its structure 30) . Thus, we calculated spectra of tetrahedral Ga and octahedral Ga shown in Fig.…”