【Others Papers】Influence of intrinsic defects on the structural, electronic and optical properties of 2D-β-Ga₂O₃ with Varying surfaces

      Researchers from the Southwest Petroleum University have published a dissertation titled "Influence of intrinsic defects on the structural, electronic and optical properties of 2D-β-Ga₂O₃ with Varying surfaces" in Materials Today Chemistry.

Abstract

      To address the future demands of artificial intelligence chips and efficient low-power devices, it is crucial to explore the intrinsic defects in the electronic and optical properties of two-dimensional (2D) wide band gap semiconductor materials with different surfaces, particularly for neural network chips, integrated circuits, photodetectors, and high properties gas sensors. In this study, we use first-principles methods to investigate the vacancy formation energies, electronic structure, and optical properties of the O and Ga vacancies in three surface structures for two-dimensional (2D) β-Ga₂O₃ (A1: Ga-exposed surface, A2: Ga and O coplanar, and A3: O-exposed surface). The results show that surface defects do not change the bulk band gap; they only introduce surface states and defect energy levels. The gaps of the surface states are only applicable to surface-localized electrons, and the bulk band gap remains unchanged. Among them, the Ga vacancies on the A1 and A3 surfaces cause the surface states to form a gap of 0.125 eV (this gap is the local transition barrier for surface electrons and has no relation to the bulk band gap). In contrast, the O(2) and Ga(2) vacancies on the A2 surface introduce defect energy levels, thereby improving electron mobility. On the A1 and A3 surfaces, the intrinsic defects are easier to form due to the presence of only one type of atom, and their surface atomic (Ga or O) defects are formed at low energies. However, for the A2 surface, the co-localization of O and Ga atoms results in high formation energies for Ga vacancies, making them more difficult to form. Furthermore, the optical properties indicate that the A2 surface has stronger UV absorption, while all three systems can enhance visible light absorption because of the presence of O(1), O(2), and Ga(1) vacancies. These findings suggest that 2D β-Ga₂O₃ with intrinsic defects can be optimized for applications such as neural network chips, integrated circuits, visible light photodetectors, and high properties gas sensors.

DOI：

https://doi.org/10.1016/j.mtchem.2025.102946