Exploring the structural, electronic, and transport properties in thickness-dependent two-dimensional Ga2O3 induced by native defects

Abstract Understanding the effects of native oxygen vacancy (VO) and gallium vacancy (VGa) in two-dimensional (2D) Ga2O3 semiconductors is critical for optimizing device efficiency and developing innovative applications. In this work, the structural stability, electronic structure, carrier mobility and conductivity of thickness-dependent 2D Ga2O3 induced by native VO and VGa are systematically studied. In Ga2O3VO configuration, the newly occupied mid-gap states primarily composed of O-2p, Ga-3p, and Ga-3d orbitals are formed, demonstrating a deep donor feature. The created impurity levels lower the bandgaps of monolayer, bilayer, and trilayer Ga2O3VO to 1.60, 1.64, and 1.53 eV, respectively. The electron mobility exhibits a high value up to ∼12 154.89 cm2V−1 s−1 in bilayer Ga2O3VO. Shallow acceptor states primarily composed of O-2p and Ga-3d orbitals are introduced for Ga2O3VGa configuration, suggesting the effective p-type doping behavior. The bandgaps of monolayer, bilayer, and trilayer Ga2O3VGa are of respectively 2.31, 1.90, and 1.84 eV, accompanying with the monotonous decreasing of hole mobilities from 261.46–85.75 cm2V−1 s−1 along x-direction. Meanwhile, the thickness dependent n-type and p-type conductivities are endowed with the similar trends as those of carrier mobilities. Distinct dimensional induced band features and transport properties have been resolved in VO and VGa cases. The high carrier mobility and strong anisotropic observed in vacancy-deficient 2D Ga2O3 highlight the insights into defect engineering strategies for next-generation wide-bandgap semiconductors.