Programme

O.6 -- Oral, VCTP-46

Date: Monday, 4 October 2021

Time: 15:10 - 15:30

Feature-Rich Electronic Properties of Carbon-Doped Silicene Nanoribbons: A First-Principles Investigations

Duy Khanh Nguyen

Institute of Applied Technology, Thu Dau Mot University

Structural and electronic properties of carbon-substituted silicene nanoribbons (SiNR) are investigated using the first-principles density functional theory (DFT) calculations. Through the DFT calculations, a complete first-principles theoretical framework is developed to fully characterize the carbon-enriched structural and electronic properties include the formation energies, optimal lattice parameters, phonon spectrum, orbital- and atom-decomposed electronic band structures, orbital- and atom-projected density of states (DOSs), spatial charge density distributions, and charge density difference along with various directions. Under C substitution effects, atomic configurations of the single C substitutions, double C substitutions under different adatom distributions of ortho, meta, and para, and full C substitutions are included in calculations, in which buckling of the pristine system is much reduced under the single and double C configurations that becomes a flat structure under the full C configuration. As a result, a typical hybridization mechanism of the quasi σ of Si-(3s,3px,3py) and C-(2s,2px,2py) and the quasi π of Si-3pz and C-2pz is formed in very strong Si-C bonds that lead to stable structures. As a close relationship, the C-diversified structures result in diverse electronic properties, in which the bandgap of the pristine system is almost opened under various C configurations. The largest opened bandgap of 2.37 eV is found at the full C configuration that is determined by quasi π bands of the highest occupied valence band of C-2pz and lowest unoccupied conduction band of Si-3pz. The C-enriched electronic properties of SiNR can be very potential for applications in optoelectronic devices. Besides, the C substitution-induced typical hybridization mechanism of the quasi σ and π orbitals that has been realized by the completely developed theoretical framework in this study can be fully generalized to other C-substituted systems.

Presenter: Nguyen Duy Khanh