| Graphene, a single-atomic layer of carbon atoms material, has unique properties over the other carbon allotropes. However, lack of band gap limits its electronic applications greatly. Among the gap-opening strategies, chemical functionalization is recognized as the popular method to modify the electronic structure of graphene, such as hydrogenation. In the past few years, more studies have been focused on the hydrogenation of graphene on both sides, like graphane. But when the graphene is on a substrate surface(SiO2), the hydrogenation on both sides of graphene is impossible and single-side hydrogenation of graphene(SSHG) is obtained, which is rarely explored both in experiments and in theories. Therefore, we systematically investigate the structural stability and electronic properties vary with the H coverage for SSHG from zero-dimensional structural motifs. Our results show that the SSHG structure with hydrogenation along armchair direction has relatively high stability, and only these SSHG structures open a band gap, which is tunable with the increasing H coverage. These findings make the hydrogenated graphene promising for applications in electronic and photonic devices. With the rise of graphene, other 2D materials also caused wide attention. 2D MoS2, which is a nonmagnetic and semiconducting compound with a direct band gap, has attracted great interest due to its potential applications in two-dimensional nanodevices. Studies extend to MoS2 nanoribbon, a restricted 2D form in one direction. Here, by using the first-principles calculation, we mainly study the structural stability, electronic and magnetic properties of MoS2 nanoribbons(zigzag and armchair) with different edge functionalizaion such as H, F, OH and defect. Our results provide theoretical guidance for their new applications in electronic devices as well as other transition metal dichalcogenides materials. |
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