First-principles investigation of a type-II BP/Sc₂CF₂ van der Waals heterostructure for photovoltaic solar cells

Constructing heterostructures has proven to be an effective strategy to manipulate the electronic properties and enlarge the application possibilities of two-dimensional (2D) materials. In this work, we perform first-principles calculations to generate the heterostructure between boron phosphide (BP) and Sc₂CF₂ materials. The electronic characteristics and band alignment of the combined BP/Sc₂CF₂ heterostructure, as well as the effects of an applied electric field and interlayer coupling, are examined. Our results predict that the BP/Sc₂CF₂ heterostructure is energetically, thermally and dynamically stable. All considered stacking patterns of the BP/Sc₂CF₂ heterostructure possess semiconducting behavior. Furthermore, the formation of the BP/Sc₂CF₂ heterostructure gives rise to the generation of type-II band alignment, which causes photogenerated electrons and holes to move in opposite ways. Therefore, the type-II BP/Sc₂CF₂ heterostructure could be a promising candidate for photovoltaic solar cells. More interestingly, the electronic properties and band alignment in the BP/Sc₂CF₂ heterostructure can be tuned by applying an electric field and modifying the interlayer coupling. Applying an electric field not only causes modulation of the band gap, but also leads to the transition from a semiconductor to a gapless semiconductor and from type-II to type-I band alignment of the BP/Sc₂CF₂ heterostructure. In addition, changing the interlayer coupling gives rise to modulation of the band gap of the BP/Sc₂CF₂ heterostructure. Our findings suggest that the BP/Sc₂CF₂ heterostructure is a promising candidate for photovoltaic solar cells.