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.

Theoretical prediction of a type-II BP/SiH heterostructure for high-efficiency electronic devices.

The generation of layered heterostructures from a combination of two or more different two-dimensional (2D) materials is considered as a powerful strategy to modify the electronic properties of 2D materials and enhance their performance in devices. Herein, using first-principles calculations, we systematically study the electronic properties and the band alignment in a heterostructure formed from 2D boron phosphide (BP) and silicane (SiH) monolayers. The BP/SiH heterostructure is structurally and mechanically stable in the ground state. The generation of the BP/SiH heterostructure leads to a reduction in the band gap, thus enhancing the optical absorption coefficient compared to the constituent BP and SiH monolayers. In addition, the BP/SiH heterostructure has a high carrier mobility of 3.2 × 104 cm2 V-1 s-1. Furthermore, the combined BP/SiH heterostructure gives rise to the formation of a type-II band alignment, inhibiting the recombination of the photogenerated carriers. The electronic properties and band alignment of the BP/SiH heterostructure can be tuned by an applied external electric field, which causes a reduction in the band gap and leads to the transition of the band alignment from type-II to type-I. Our findings could act as theoretical guidance for the use of the BP/SiH heterostructure in the design of high-efficiency nanodevices.