Local Structure of Zn Dopant in β-Phase Ga2O3

Ga2O3 is a promising ultrawide-bandgap semiconductor for high-voltage and high-power applications, yet achieving reliable p-type electrical conductivity remains a significant challenge. We utilized halide vapor phase epitaxy growth to synthesize epitaxial layers of β-phase Ga2O3 doped with Zn, which can serve as a suitable acceptor. Thin-film samples with Zn doping concentrations of 1.7 × 1019 and 2.5 × 1020 ions/cm3 were confirmed as single phases of monoclinic β-Ga2O3 by X-ray diffraction. To determine the location of Zn ions within the β-Ga2O3 lattice, we employed X-ray absorption near-edge structure (XANES) in conjunction with first-principles density functional theory calculations. Theoretical XANES spectra for Zn substitutions in the tetrahedral and octahedral Ga sites in β-Ga2O3, as well as a precipitation of ZnGa2O4 spinel, were compared with the experimental data. The experimental XANES spectra of the Zn L3 edge were reproduced well by theoretical spectra of Zn ions occupied at cationic positions at the tetrahedral coordinated site.