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 (V O ) and gallium vacancy (V Ga ) in two-dimensional (2D) Ga 2 O 3 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 Ga 2 O 3 induced by native V O and V Ga are systematically studied. In Ga 2 O 3 V O 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 Ga 2 O 3 V O to 1.60, 1.64, and 1.53 eV, respectively. The electron mobility exhibits a high value up to ∼12 154.89 cm 2 V −1 s −1 in bilayer Ga 2 O 3 V O . Shallow acceptor states primarily composed of O-2p and Ga-3d orbitals are introduced for Ga 2 O 3 V Ga configuration, suggesting the effective p-type doping behavior. The bandgaps of monolayer, bilayer, and trilayer Ga 2 O 3 V Ga are of respectively 2.31, 1.90, and 1.84 eV, accompanying with the monotonous decreasing of hole mobilities from 261.46–85.75 cm 2 V −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 V O and V Ga cases. The high carrier mobility and strong anisotropic observed in vacancy-deficient 2D Ga 2 O 3 highlight the insights into defect engineering strategies for next-generation wide-bandgap semiconductors.