Exploring Intrinsic and Extrinsic p-Type Dopability of Atomically Thin β-TeO₂ from First Principles

Area of Science:

• Materials Science
• Condensed Matter Physics
• Semiconductor Physics

Background:

• Two-dimensional (2D) β-TeO₂ is a transparent material with high hole mobility, making it attractive for optoelectronic and power devices.
• The fundamental mechanisms governing its p-type conductivity and dopability are not well understood.
• Understanding these mechanisms is crucial for optimizing its performance in electronic applications.

Purpose of the Study:

• To investigate the role of intrinsic and extrinsic point defects in the p-type conductivity of monolayer and bilayer β-TeO₂.
• To explore potential dopants for achieving p-type conductivity in 2D β-TeO₂.
• To elucidate the mechanisms responsible for hole conduction in this material.

Main Methods:

• Utilized the Heyd-Scuseria-Ernzerhof (HSE) + D3 hybrid functional for theoretical calculations.
• Studied intrinsic and extrinsic point defects in both monolayer and bilayer β-TeO₂.
• Investigated substitutional doping with ten trivalent elements.

Main Results:

• Most intrinsic defects do not contribute to p-type doping in 2D β-TeO₂.
• Silicon and hydrogen contamination can degrade p-type conductivity.
• Hole conduction is likely due to hopping via localized impurity states or substrate effects.
• Bismuth (Bi) shows a shallow acceptor level, but all dopants create deep localized states.
• Monolayer β-TeO₂ offers advantages over bilayers due to reduced self-compensation.

Conclusions:

• Intrinsic defects are not the primary source of p-type conductivity in 2D β-TeO₂.
• Alternative mechanisms like hopping conduction and substrate effects are proposed.
• Bismuth doping is a potential route, but defect states need careful management.
• Monolayer 2D β-TeO₂ is promising for p-type doping due to reduced self-compensation, offering a pathway for defect engineering in electronic devices.