First-Principles Study of Strain Modulation in S3P2/Black Phosphorene vdW Heterostructured Nanosheets for Flexible Electronics

Strain is an effective way to modulate the electronic state of semiconductors and improve the performance of semiconductor devices. Here, we propose a monolayer flexible material of S3P2 to implement the strain on black phosphorene (BP). The stability, carrier mobility, and electronic structure of S3P2/BP van der Waals (vdW) heterostructure have been explored by utilizing first-principles calculations. Taking into account the stacking pattern between the S3P2 and BP sheets as the most stable one, we find that the AB(1) pattern is sensitive to in-plane strain on the electronic and optical properties. Our results show that the indirect-direct band gap transition can be observed when the biaxial tensile strain increases up to 3%. Additionally, there is a drop/jump for the obvious anisotropy of the electronic effective mass along the x/y direction at the state of indirect-direct band gap transition. Meanwhile, with an increasing tensile strain, the ultraviolet region of the absorption spectra is greatly enhanced in AB(1) stacking pattern. Our results suggest that the proposed system could potentially be applied as flexible electronic and optoelectronic devices.