Unique BiCuOSe/Bi2O2Se van der Waals monolayer with ultra-high electron mobility

Abstract

In this study, based on first-principles calculations, we propose a new BiCuOSe/Bi₂O₂Se van der Waals monolayer that shows a direct band gap and exhibits excellent mechanical and thermodynamic stability. In this monolayer, the reduced conduction band overlap in Bi atoms due to lattice strain suppresses the originally strong coulomb interactions between electrons. In addition, the intrinsic separation of electron and hole transport channels in the BiCuOSe/Bi₂O₂Se monolayer enables high electron transport. Surprisingly, an ultra-high electron mobility of 1160.0 cm² V⁻¹ s⁻¹ in the Bi₂O₂Se layer of the BiCuOSe/Bi₂O₂Se monolayer along the b-axis is generated at 300 K, far surpassing the electron mobility of bulk Bi₂O₂Se (370 cm² V⁻¹ s⁻¹) and the Bi₂O₂Se monolayer (280 cm² V⁻¹ s⁻¹). These findings highlight the potential application of BiCuOSe/Bi₂O₂Se for future electronic devices and provide a new strategy to obtain a high electron transport performance heterostructure.