A large enhancement of carrier mobility in phosphorene by introducing hexagonal boron nitride substrate

TL;DR

This study demonstrates that placing phosphorene on a hexagonal boron nitride substrate significantly enhances its carrier mobility by leveraging the substrate's mechanical and dielectric properties, promising improved 2D electronic devices.

Contribution

The paper provides a first-principles analysis of how h-BN substrates enhance phosphorene's carrier mobility, elucidating the underlying mechanics and preserving electronic properties.

Findings

Carrier mobility in phosphorene is significantly increased on h-BN substrate.

The high elastic modulus of h-BN contributes to mobility enhancement.

Electronic properties of phosphorene are preserved near the Fermi level.

Abstract

Carrier mobility is a crucial character for electronic devices since it domains power dissipation and switching speed. Materials with certain high carrier mobility, equally, unveil rich unusual physical phenomena elusive in their conventional counterparts. As a consequence, the methods to enhance the carrier mobility of materials receive immense research interests due to their potential applications in more effective electronic devices and enrichment of more unusual phenomena. For instance, introducing a flat hexagonal boron nitride (h-BN) substrate to enhance the carrier mobility has been achieved experimentally. However, the underlying mechanics is not well understood. In this study, we estimate the carrier mobility of phosphorene on h-BN substrate (P/h-BN) within the framework of the phonon-limited scattering model at first-principles level. %Our results are generic. Besides high-$\kappa$ dielectric property, h-BN also possesses excellent mechanical property of a high two-dimensional elastic modulus. The P/h-BN heterostructure inherits the high elastic modulus of h-BN, leading to an enhanced carrier mobility in phosphorene. Owing to the weak van der Waals interactions between the layers, the unique electronic properties of phosphorene are almost perfectly preserved near the Fermi level, guaranteeing the superior electronic transport in P/h-BN. Our findings offer a new perspective to improve the carrier mobility in phosphorene as well as other 2D materials based field effect transistors.