Raman Spectroscopic Characterization of Chemical Bonding and Phase Segregation in Tin (Sn)-Incorporated Ga2O3.

Using detailed Raman scattering analyses, the effect of tin (Sn) incorporation on the crystal structure, chemical bonding/inhomogeneity, and single-phase versus multiphase formation of gallium oxide (Ga2O3) compounds is reported. The Raman characterization of the Sn-mixed Ga2O3 polycrystalline compounds (0.00 ≤ x ≤ 0.30), which were produced by the high-temperature solid-state synthesis method, indicated that the Sn-induced changes in the chemical bonding and phase segregation were significant. Furthermore, the evolution of Sn-O bonds with increasing Sn concentration (x) was confirmed. While the monoclinic β-Ga2O3 was unperturbed for lower x values, Raman spectra revealed the nucleation of a composite with a distinct SnO2 secondary phase. A higher Sn content led to the formation of a Ga-Sn-O + SnO2 mixed phase compound, which was reflected in shifts in the high-frequency stretching and bending of the GaO4 tetrahedra that structurally formed the β-Ga2O3 phase. Thus, a chemical composition/phase/chemical bonding correlation was established for the Sn-incorporated Ga2O3 compounds.