The development of low contact resistance at metal-semiconductor interfaces in next-generation transistors is being prioritized to improve device performance. By using density functional theory, an intrinsic Ohmic contact between a wide band gap semiconductor MgS and semimetal graphene is predicted herewith theoretically. The zero Schottky barriers in graphene/MgS van der Waals heterostructure (vdWH) can facilitate a high charge injection efficiency, whereas Ohmic contact can be induced in graphene/MgSe under small external perturbation. A comprehensive investigation of the modulation in the electronic contact properties is conducted under the application of vertical compressive strain and a perpendicular electric field to understand their role in the transport mechanism. Under vertical compressive strain, a band gap of ∼0.62 eV in graphene has been opened up. While under perpendicular electric field, the hole carrier concentration in graphene is found to be increased up to $\sim {10}^{14}\mathrm{c}{\mathrm{m}}^{–2}$. Moreover, this work circumvents the prevalent approaches in inducing an Ohmic contact and addresses solutions to very fundamental challenges in pristine graphene, i.e., band gap opening and its tunability, and modulation of carrier concentration. These interesting properties of vdWHs can open up new avenues for constructing these heterojunctions for multifunctional graphene-based field-effect transistors.

中文翻译：

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通过应变和电场有效调节带隙开口可调的石墨烯-MgX(X=S,Se) 范德华异质结中的欧姆接触和载流子浓度

下一代晶体管金属-半导体界面处低接触电阻的开发正在优先考虑以提高器件性能。通过使用密度泛函理论，从理论上预测了宽带隙半导体 MgS 和半金属石墨烯之间的本征欧姆接触。石墨烯/MgS 范德华异质结构（vdWH）中的零肖特基势垒可以促进高电荷注入效率，而在小的外部扰动下可以在石墨烯/MgSe 中诱导欧姆接触。在垂直压缩应变和垂直电场的应用下，对电子接触特性的调制进行了全面研究，以了解它们在传输机制中的作用。在垂直压缩应变下，带隙约为 0。石墨烯中的 62 eV 已被打开。在垂直电场下，发现石墨烯中的空穴载流子浓度增加到$～{10}^{14}\mathrm{C}{\mathrm{米}}^{——2}$. 此外，这项工作绕过了诱导欧姆接触的流行方法，并解决了原始石墨烯中非常基本的挑战的解决方案，即带隙开放及其可调谐性，以及载流子浓度的调制。vdWH 的这些有趣特性可以为构建这些异质结开辟新的途径，用于多功能石墨烯基场效应晶体管。