Achievement of strain-driven ultrahigh carrier mobility in β-TeO2

Abstract

Layered crystals of β-TeO2 with high carrier mobility and wider bandgap could be a promising candidate for nanoelectronics applications. Suitable mechanical flexibility permits strain-engineering in such layered structures to introduce anisotropy associated with electron and hole mobility. In this context, we have used the ab-initio based density functional theory (DFT) method along with the Boltzmann transport equation (BTE) to explore the strain-induced charge carrier anisotropy in mobility for β-TeO2. Furthermore, the lone pair associated with tellurium atoms leads to additional transport anisotropy in electron and hole mobility. Interestingly, the application of critical uniaxial compressive strain results in sudden amplification of carrier mobility, which has been discussed based on carrier scattering information and anisotropy in carrier effective mass derived from electronic dispersion curve. The strong electron and hole anisotropy in mobility can also be realized in terms of higher carrier relaxation time under uniaxial strain. Finally, all these findings make layered β-TeO2 an emerging candidate for power electronics applications and advanced transport devices.