AI 中文总结
本研究通过第一性原理计算，探究三种石墨烯基二维范德华异质结构，利用电调控和层间耦合可调控其肖特基接触类型、能带排列，还分析了光学响应与激子结合能，为相关器件设计提供理论依据。
AI 中文摘要
包含石墨烯（GE）的范德华异质结构（vdW HTSs）因具备制备出多种应用器件的潜力，成为理论与实验研究的活跃领域。本文采用第一性原理计算，研究了C₆N₆/GE、hg-C₃N₄/GE和C₆N₆/hg-C₃N₄这三种二维范德华异质结构，系统分析了半导体/金属及半导体/半导体界面的结构与热力学稳定性、电子性质、力学性质和光学性质。两种半导体/金属异质结构均形成n型肖特基接触，通过调控外加垂直电场和层间耦合，可将其转化为p型肖特基接触或欧姆接触。在半导体/半导体C₆N₆/hg-C₃N₄异质结构中，价带顶和导带底源自不同层，形成II型能带排列，可促进高效的电子-空穴（e-h）分离；外加电场和改变层间距，能有效将其能带排列在I型与II型之间调控。从异质结构的光吸收光谱可知，C₆N₆/GE和hg-C₃N₄/GE在宽频率范围内表现出光学响应，而C₆N₆/hg-C₃N₄异质结构主要在紫外区有显著活性。采用G₀W₀+BSE方法，计算了带隙体系（即C₆N₆单层、hg-C₃N₄单层及其异质结构C₆N₆/hg-C₃N₄）的激子结合能，分别为1.01 eV、1.14 eV和1.18 eV，凸显出强电子-空穴相互作用；此外，C₆N₆/hg-C₃N₄异质结构的带边分析进一步表明其有利于显著的层间电子-空穴耦合。
英文摘要
Van der Waals heterostructures (vdW HTSs) incorporating graphene (GE) have been an active area of research, both theoretical and experimental, due to their potential to yield devices with a wide variety of applications. In this paper, first-principles calculations are employed to investigate C$_{6}$N$_{6}$/GE, hg-C$_{3}$N$_{4}$/GE, and C$_{6}$N$_{6}$/hg-C$_{3}$N$_{4}$ 2D vdW HTSs. A systematic analysis of structural and thermodynamic stability, electronic, mechanical, and optical properties of semiconductor/metal and semiconductor/semiconductor interfaces is performed. Both semiconductor/metal HTSs form $n$-type Schottky contacts, which can be converted into $p$-type Schottky or Ohmic contacts by tuning the external perpendicular electric field and the interlayer coupling. In the semiconductor/semiconductor C$_{6}$N$_{6}$/hg-C$_{3}$N$_{4}$ HTS, the valence and conduction band edges originate from distinct layers, resulting in a type-II band alignment that promotes efficient electron-hole (e-h) separation. Furthermore, the band alignment can be effectively tuned between type-I and type-II by applying an external electric field and varying the interlayer distance. From the optical absorption spectra of the HTSs, we concluded that the C$_{6}$N$_{6}$/GE and hg-C$_{3}$N$_{4}$/GE exhibit an optical response across a wide frequency range, whereas the C$_{6}$N$_{6}$/hg-C$_{3}$N$_{4}$ HTS shows prominent activity primarily in the ultraviolet region. Using the $G_{0}W_{0}$+BSE approach, the exciton binding energies are also calculated for the gapped systems, namely C$_{6}$N$_{6}$, hg-C$_{3}$N$_{4}$ monolayers, and their HTS (C$_{6}$N$_{6}$/hg-C$_{3}$N$_{4}$), yielding values of 1.01 eV, 1.14 eV, and 1.18 eV, respectively, highlighting strong e-h interactions. Moreover, the band-edge analysis of C$_{6}$N$_{6}$/hg-C$_{3}$N$_{4}$ HTS further favors pronounced interlayer e-h coupling.
CommentsMain Manuscript: 13 figures, 16 pages. Supplemental Material: 9 figures, 6 pages
Journal refPhys. Rev. B 114, 105301 (2026)
