%0 Journal Article
%T Effect and Characterization of Stone¨CWales Defects on Graphene Quantum Dot: A First-Principles Study
%A Arka Bandyopadhyay
%A Debnarayan Jana
%A Gargi Chakraborti (Banerjee)
%J Condensed Matter | An Open Access Journal from MDPI
%D 2018
%R https://doi.org/10.3390/condmat3040050
%X Abstract A first principles based density functional theory (DFT) has been employed to identify the signature of Stone¨CWales (SW) defects in semiconducting graphene quantum dot (GQD). Results show that the G mode in the Raman spectra of GQD has been red shifted to 1544.21 cm £¿ 1 in the presence of 2.08% SW defect concentration. In addition, the intensity ratio between a robust low intense contraction¨Celongation mode and G mode is found to be reduced for the defected structure. We have also observed a Raman mode at 1674.04 cm £¿ 1 due to the solo contribution of the defected bond. The increase in defect concentration, however, reduces the stability of the structures. As a consequence, the systems undergo structural buckling due to the presence of SW defect generated additional stresses. We have further explored that the 1615.45 cm £¿ 1 Raman mode and 1619.29 cm £¿ 1 infra-red mode are due to the collective stretching of two distinct SW defects separated at a distance 7.98 £¿. Therefore, this is the smallest separation between the SW defects for their distinct existence. The pristine structure possesses maximum electrical conductivity and the same reduces to 0.37 times for 2.08% SW defect. On the other hand, the work function is reduced in the presence of defects except for the structure with SW defects separated at 7.98 £¿. All these results will serve as an important reference to facilitate the potential applications of GQD based nano-devices with inherent topological SW defects. View Full-Tex
%K density functional theory (DFT)
%K Raman spectroscopy
%K Stone¨CWales defect
%K electronic properties
%K infra-red spectra
%U https://www.mdpi.com/2410-3896/3/4/50