Exploring Intrinsic and Extrinsic <i>p</i>-Type Dopability of Atomically Thin β-TeO<sub>2</sub> from First Principles
Rafael Costa-Amaral, Soungmin Bae, Vu Thi Ngoc Huyen, Yu Kumagai
Abstract
High Resolution Image Download MS PowerPoint Slide Two-dimensional (2D) β-TeO 2 has gained attention as a promising material for optoelectronic and power device applications, thanks to its transparency and high hole mobility. However, the mechanisms driving its p -type conductivity and dopability remain elusive. In this study, we investigate the intrinsic and extrinsic point defects in monolayer and bilayer β-TeO 2, the latter of which has been experimentally synthesized, using the Heyd–Scuseria–Ernzerhof (HSE) + D3 hybrid functional. Our results reveal that most intrinsic defects are unlikely to contribute to p -type doping in 2D β-TeO 2 . Moreover, Si and H contamination could further impair p -type conductivity. Since the point defects do not contribute to p -type conductivity, we suggest two possible mechanisms for hole conduction: hopping conduction via localized impurity states, and substrate effects. We also explored substitutional p -type doping in 2D β-TeO 2 with 10 trivalent elements. Among these, the Bi dopant is found to exhibit a relatively shallow acceptor transition level. However, all the dopants introduce deep localized states, where hole polarons are trapped by the lone pairs of Te atoms. Interestingly, monolayer β-TeO 2 shows potential advantages over bilayers due to reduced self-compensation effects for p -type dopants. These findings provide valuable insights into defect engineering strategies for future electronic applications involving 2D β-TeO 2 .