Semiconductor-to-metal transition in bilayer MoSi$_2$N$_4$ and WSi$_2$N$_4$ with strain and electric field

TL;DR

This study demonstrates how strain and electric fields can effectively tune the electronic properties of bilayer MoSi2N4 and WSi2N4, enabling transitions from semiconductor to metal and from indirect to direct band gaps, crucial for nanoelectronic applications.

Contribution

It is the first to systematically explore band structure engineering of bilayer MoSi2N4 and WSi2N4 using strain and electric fields.

Findings

Strain induces indirect-to-direct band gap transition.

Electric field causes semiconductor-to-metal transition.

Provides a pathway for electronic property tuning in 2D materials.

Abstract

With exceptional electrical and mechanical properties and at the same time air-stability, layered MoSi2N4 has recently draw great attention. However, band structure engineering via strain and electric field, which is vital for practical applications, has not yet been explored. In this work, we show that the biaxial strain and external electric field are effective ways for the band gap engineering of bilayer MoSi$_2$N$_4$ and WSi$_2$N$_4$. It is found that strain can lead to indirect band gap to direct band gap transition. On the other hand, electric field can result in semiconductor to metal transition. Our study provides insights into the band structure engineering of bilayer MoSi$_2$N$_4$ and WSi$_2$N$_4$ and would pave the way for its future nanoelectronics and optoelectronics applications.