Exploring the structural, electronic, and transport properties in thickness-dependent two-dimensional Ga2O3induced by native defects.

Abstract

Understanding the effects of native oxygen vacancy (V_O) and gallium vacancy (V_Ga) in two-dimensional (2D) Ga₂O₃semiconductors 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 Ga₂O₃induced by native V_Oand V_Gaare systematically studied. In Ga₂O₃V_Oconfiguration, 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 Ga₂O₃V_Oto 1.60, 1.64, and 1.53 eV, respectively. The electron mobility exhibits a high value up to ∼12 154.89 cm²V^-1s^-1in bilayer Ga₂O₃V_O. Shallow acceptor states primarily composed of O-2p and Ga-3d orbitals are introduced for Ga₂O₃V_Gaconfiguration, suggesting the effective p-type doping behavior. The bandgaps of monolayer, bilayer, and trilayer Ga₂O₃V_Gaare of respectively 2.31, 1.90, and 1.84 eV, accompanying with the monotonous decreasing of hole mobilities from 261.46-85.75 cm²V^-1s^-1alongx-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_Oand V_Gacases. The high carrier mobility and strong anisotropic observed in vacancy-deficient 2D Ga₂O₃highlight the insights into defect engineering strategies for next-generation wide-bandgap semiconductors.