Hybrid Density Functional\nStudy on the <i>p</i>‑Type Conductivity Mechanism\nin Intrinsic Point Defects and\nGroup V Element-Doped 2D β‑TeO<sub>2</sub>

The newly discovered two-dimensional (2D) β-TeO<sub>2</sub> possesses extraordinarily high <i>p</i>-type carrier\nmobility\nand demonstrates immense potential in the electronics field. However,\ncurrent research on its <i>p</i>-type conductivity mechanisms\nand the modifications of element doping remains relatively insufficient.\nIn this study, the intrinsic point defects and extrinsic element doping\nin monolayer β-TeO<sub>2</sub> are comprehensively analyzed\nto probe the potential sources of the intrinsic <i>p</i>-type conductivity and the extrinsic <i>p</i>-type doping\npossibility in 2D β-TeO<sub>2</sub> through hybrid density functional\ncalculations. Our results reveal that the vacancy defects with low\nformation energies have deep transition levels and thus cannot be\nused as sources of unintentional <i>p</i>-type conductivity\nin 2D β-TeO<sub>2</sub>. The investigations and discussions\nvia Group V element doping modifications in 2D β-TeO<sub>2</sub> indicate that bismuth (Bi) doping can easily and significantly enhance\nthe <i>p</i>-type conductivity of 2D β-TeO<sub>2</sub> under the presence of O-rich, which can be achieved experimentally.\nFurthermore, Bi doping can significantly increase carrier mobility\nwithout seriously affecting the electronic structure. The finding\nshows that the Bi element is an ideal dopant candidate for a <i>p</i>-type modification in 2D β-TeO<sub>2</sub>. Our calculations\npave an alternative strategy to achieve the realization of superior <i>p</i>-type conductivity in 2D β-TeO<sub>2</sub>.