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Two-dimensional (2D) Janus materials have attracted the interest of scholars due to their asymmetric structure and unique physical properties. Recently, the 2D Janus MoSiGeN4 based on MoSi2N4 has been predicted. Here, the structure, electronic character, and carrier mobility of a bilayer in different stacks are investigated using the first-principles calculations. The results show that the dipole moment perpendicular to the x-y plane plays a dominant role in regulating the bandgap, which can be supported by the difference in vacuum energy levels between the two sides of the material. The layer stack has a dramatic effect on the bandgap, which is reduced to 0.57 eV for a bilayer structure. Further exploration of the electronic structure reveals that the bilayer energy band exhibits the type II energy band alignment, which is beneficial for the separation of photogenerated carriers. The bilayer boosts electron mobility by an order of magnitude to 58 522.3 cm2 V−1 s−1 for the monolayer. The results demonstrate the potential of the bilayer MoSiGeN4 for photocatalytic water splitting and electronic devices.

2D/3D heterostructures have received extensive attention due to their unique structures and outstanding properties. In this work, the structural and electronic properties of monolayer MoS2/4H-SiC(Si-face) heterojunctions are systematically investigated through density functional theory calculation and experimental analysis. The calculated results show that the monolayer MoS2/4H-SiC heterostructure is a van der Waals heterojunction because of low formation energy and shows a type-II band alignment with a valence band offset of 1.43 eV. Then the type-II band alignment of the MoS2/4H-SiC heterostructure is verified by x-ray photoelectron spectroscopy. However, there is a deviation of 0.44 eV in the valence band offset between the calculated results and the experimental data, which may be caused by the underestimation of the bandgap by the Perdew–Burke–Ernzerhof method and the introduction of impurities at the interface. Our experimental results reveal the type of band alignment and the combination of the MoS2/4H-SiC heterostructure interface, which is an effective way to understand and design photocatalysts and electronic devices.

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