Tuning of the electronic and optical properties of single layer black phosphorus by strain

TL;DR

This study uses first principles calculations to show that strain can significantly alter the electronic and optical properties of single-layer black phosphorus, enabling potential applications in photovoltaic device design.

Contribution

The paper demonstrates the strong dependence of black phosphorus's properties on strain and highlights the importance of many-body effects for accurate predictions.

Findings

Strain significantly affects electronic conductivity and optical response.

Many-body effects are essential for accurate electronic property description.

Optical band gap can be tuned from 0.38 eV to 2.07 eV with strain.

Abstract

Using first principles calculations we showed that the electronic and optical properties of single layer black phosphorus (BP) depend strongly on the applied strain. Due to the strong anisotropic atomic structure of BP, its electronic conductivity and optical response are sensitive to the magnitude and the orientation of the applied strain. We found that the inclusion of many body effects is essential for the correct description of the electronic properties of monolayer BP; for example while the electronic gap of strainless BP is found to be 0.90 eV by using semilocal functionals, it becomes 2.31 eV when many-body effects are taken into account within the G0W0 scheme. Applied tensile strain was shown to significantly enhances electron transport along zigzag direction of BP. Furthermore, biaxial strain is able to tune the optical band gap of monolayer BP from 0.38 eV (at -8% strain) to 2.07 eV (at 5.5%). The exciton binding energy is also sensitive to the magnitude of the applied strain. It is found to be 0.40 eV for compressive biaxial strain of -8%, and it becomes 0.83 eV for tensile strain of 4%. Our calculations demonstrate that the optical response of BP can be significantly tuned using strain engineering which appears as a promising way to design novel photovoltaic devices that capture a broad range of solar spectrum.