Van der Waals (vdW) heterostructures are ordinarily employed to furnish more possibilities for two-dimensional (2D) semiconductor materials. In this work, we explore thoroughly the electronic and optical properties of AlN/C₂N heterostructure based on first-principles. The results reveal that the heterostructure with an indirect bandgap is a semiconductor material that is stable in energy and made by vdW interaction. The AlN/C₂N heterostructure has type-II band alignment that can availably facilitate the segregation of photogenerated carriers and prolong the longevity of the carriers, and the built-in electric field (E_int) formed inside the heterostructure can further encourage them. The band edge position crossing the water-splitting redox potential states that the heterostructure can serve to water-splitting catalytic process, while water oxidation and reduction reactions befell in the AlN layer and the C₂N layer, respectively. Moreover, the heterostructure has higher carrier mobility and stronger light absorption capacity in the near-ultraviolet and visible light regions compared to two monolayers. It is worth noting that the light absorption of the heterostructure has redshift under compressive biaxial strain. The work demonstrates that the 2D AlN/C₂N heterostructure has the compelling potential to be used as an efficient water-splitting photocatalyst and used for other optical devices.

通常采用范德华（vdW）异质结构为二维（2D）半导体材料提供更多可能性。在这项工作中，我们基于第一性原理彻底探索了AlN / C ₂ N异质结构的电子和光学性质。结果表明，具有间接带隙的异质结构是一种能量稳定且由vdW相互作用制得的半导体材料。AlN / C ₂ N异质结构具有II型能带排列，可以有效地促进光生载流子的分离并延长载流子的寿命以及内置电场（E _int）形成在异质结构内部可以进一步鼓励它们。跨越水分解氧化还原电势的能带边缘位置表明，异质结构可用于水分解催化过程，而水的氧化和还原反应分别发生在AlN层和C ₂ N层中。而且，与两个单层相比，异质结构在近紫外和可见光区域具有更高的载流子迁移率和更强的光吸收能力。值得注意的是，异质结构的光吸收在压缩双轴应变下具有红移。这项工作证明了2D AlN / C ₂N异质结构具有引人注目的潜力，可以用作有效的水分解光催化剂并用于其他光学器件。