Abstract
The impacts of the hydrogenation method and hydrogenation concentration on the plasmon excitations in hydrogenated silicene nanostructures are studied by the time-dependent density functional theory. Chair and Z-line conformations of the hydrogenated silicene nanostructure are mainly considered. When the whole silicene nanostructure is hydrogenated, because the delocalized π electrons form sp3 hybrid orbitals, the low energy plasmon resonance mode disappears. Compared with the hydrogenation that occurred in the middle area of nanostructure, when the hydrogenation occurred in the boundary area, the resonance intensity of the low-energy plasmon decreases greatly. In the high energy region, hydrogenation methods have important effects on plasmon excitation. For the chair-conformation hydrogenated silicene nanostructure, compared with pure silicene nanostructures, the band of high energy plasmon resonance spreads toward the low energy end. However, for the Z-line conformation hydrogenated silicene nanostructure, both the resonance band and the main absorption peak of the high energy plasmon have a blue shift. Moreover, the shape of the resonance band of high energy plasmon is different for hydrogenated silicene nanostructures of different conformations.
Highlights
Silicene, which is a kind of monolayer silicon film in a buckled honeycomb lattice, represents a monoelemental class of twodimensional materials similar to graphene.[1–12] Because of its exotic electronic properties and compatibility with current silicon-based electronics, it has been attracting people’s attention in recent years
When the impulse excitation is polarized in the armchair-edge direction, compared with pure nanostructures,[29] the band of high energy plasmon resonance spreads toward the low energy end
Using the time-dependent density functional theory, we have carried out a systematic study of plasmon excitations of the two kinds of hydrogenated silicene nanostructures and mainly investigated the impacts of the hydrogenation method and hydrogenation concentration on the plasmon excitations
Summary
Silicene, which is a kind of monolayer silicon film in a buckled honeycomb lattice, represents a monoelemental class of twodimensional materials similar to graphene.[1–12] Because of its exotic electronic properties and compatibility with current silicon-based electronics, it has been attracting people’s attention in recent years. Through different methods, silicene has been synthesized. Due to the absence of a graphite-like form of silicon in nature, silicene is synthesized by epitaxial growth on a substrate. Especially hydrogenation, are used to tailor the electronic properties of silicene effectively.[17–19]. It has been reported that, in the hydrogenated silicene sheets, the silicon atoms form different conformations, such as the chair and Z-line conformations.[18]. The bandgap of silicene can be tuned by varying hydrogen coverage, which is of the utmost importance for electronic applications
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