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Analytical performance of 3 m and 3 m +1 armchair graphene nanoribbons under uniaxial strain.

Kang ES, Ismail R - Nanoscale Res Lett (2014)

Bottom Line: Discrepancies between the classical calculation and quantum calculation were also measured.It has been found that as much as 19% of the drive current loss is due to the quantum confinement.These analytical models which agree well with the experimental and numerical results provide physical insights into the characterizations of uniaxial strained AGNRs.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Electronic and Computer Engineering, Southern University College, Skudai 81310, Johor Darul Takzim, Malaysia.

ABSTRACT
The electronic band structure and carrier density of strained armchair graphene nanoribbons (AGNRs) with widths of n =3 m and n =3 m +1 were examined using tight-binding approximation. The current-voltage (I-V) model of uniaxial strained n =3 m AGNRs incorporating quantum confinement effects is also presented in this paper. The derivation originates from energy dispersion throughout the entire Brillouin zone of uniaxial strained AGNRs based on a tight-binding approximation. Our results reveal the modification of the energy bandgap, carrier density, and drain current upon strain. Unlike the two-dimensional graphene, whose bandgap remains near to zero even when a large strain is applied, the bandgap and carrier density of AGNRs are shown to be sensitive to the magnitude of uniaxial strain. Discrepancies between the classical calculation and quantum calculation were also measured. It has been found that as much as 19% of the drive current loss is due to the quantum confinement. These analytical models which agree well with the experimental and numerical results provide physical insights into the characterizations of uniaxial strained AGNRs.

No MeSH data available.


Related in: MedlinePlus

Variation of carrier density at room temperature in AGNRs. The variation of carrier density at room temperature in AGNRs in respect to the normalized Fermi energy for two different families (a) n =3 m and (b) n =3 m +1.
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Figure 4: Variation of carrier density at room temperature in AGNRs. The variation of carrier density at room temperature in AGNRs in respect to the normalized Fermi energy for two different families (a) n =3 m and (b) n =3 m +1.

Mentions: Figure 4 plots the analytical carrier density at room temperature as a function of the normalized Fermi energy ηF at different magnitudes of strain. While the nondegenerate case has a strict linear curve (in logarithmic scale) with a high slope, the degenerate carrier density has a quasi linear curve and a reduced slope. More precisely, the slope of log(n) in the degenerate case is not constant but rather gradually decreases with EF − Ec/kBT. The influence of uniaxial strain on the carrier density of AGNRs is significant and quantitatively different for the two families. These figures show that for n =3 m AGNRs, uniaxial strain increases the carrier density, while on the contrary, n =3 m +1 AGNRs show a reduction in carrier density upon strain. Figure 5 plots the dependence of carrier density of different widths on the uniaxial strain at room temperature. The AGNRs with narrow ribbon width exhibit large charge modulation due to the existence of a gap, and the effect of the uniaxial strain on the characteristics of the carrier density of AGNRs shows family behavior. The carrier densities of the two families of AGNRs change accordingly to the magnitude of the strain, but for n =3 m +1 AGNRs, the carrier density does not change linearly, as in n =3 m AGNRs. Instead, one can observe turning points for w =2.090 nm and w =3.197 nm, as supported by previous observations in Figures 2 and 3.


Analytical performance of 3 m and 3 m +1 armchair graphene nanoribbons under uniaxial strain.

Kang ES, Ismail R - Nanoscale Res Lett (2014)

Variation of carrier density at room temperature in AGNRs. The variation of carrier density at room temperature in AGNRs in respect to the normalized Fermi energy for two different families (a) n =3 m and (b) n =3 m +1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4231444&req=5

Figure 4: Variation of carrier density at room temperature in AGNRs. The variation of carrier density at room temperature in AGNRs in respect to the normalized Fermi energy for two different families (a) n =3 m and (b) n =3 m +1.
Mentions: Figure 4 plots the analytical carrier density at room temperature as a function of the normalized Fermi energy ηF at different magnitudes of strain. While the nondegenerate case has a strict linear curve (in logarithmic scale) with a high slope, the degenerate carrier density has a quasi linear curve and a reduced slope. More precisely, the slope of log(n) in the degenerate case is not constant but rather gradually decreases with EF − Ec/kBT. The influence of uniaxial strain on the carrier density of AGNRs is significant and quantitatively different for the two families. These figures show that for n =3 m AGNRs, uniaxial strain increases the carrier density, while on the contrary, n =3 m +1 AGNRs show a reduction in carrier density upon strain. Figure 5 plots the dependence of carrier density of different widths on the uniaxial strain at room temperature. The AGNRs with narrow ribbon width exhibit large charge modulation due to the existence of a gap, and the effect of the uniaxial strain on the characteristics of the carrier density of AGNRs shows family behavior. The carrier densities of the two families of AGNRs change accordingly to the magnitude of the strain, but for n =3 m +1 AGNRs, the carrier density does not change linearly, as in n =3 m AGNRs. Instead, one can observe turning points for w =2.090 nm and w =3.197 nm, as supported by previous observations in Figures 2 and 3.

Bottom Line: Discrepancies between the classical calculation and quantum calculation were also measured.It has been found that as much as 19% of the drive current loss is due to the quantum confinement.These analytical models which agree well with the experimental and numerical results provide physical insights into the characterizations of uniaxial strained AGNRs.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Electronic and Computer Engineering, Southern University College, Skudai 81310, Johor Darul Takzim, Malaysia.

ABSTRACT
The electronic band structure and carrier density of strained armchair graphene nanoribbons (AGNRs) with widths of n =3 m and n =3 m +1 were examined using tight-binding approximation. The current-voltage (I-V) model of uniaxial strained n =3 m AGNRs incorporating quantum confinement effects is also presented in this paper. The derivation originates from energy dispersion throughout the entire Brillouin zone of uniaxial strained AGNRs based on a tight-binding approximation. Our results reveal the modification of the energy bandgap, carrier density, and drain current upon strain. Unlike the two-dimensional graphene, whose bandgap remains near to zero even when a large strain is applied, the bandgap and carrier density of AGNRs are shown to be sensitive to the magnitude of uniaxial strain. Discrepancies between the classical calculation and quantum calculation were also measured. It has been found that as much as 19% of the drive current loss is due to the quantum confinement. These analytical models which agree well with the experimental and numerical results provide physical insights into the characterizations of uniaxial strained AGNRs.

No MeSH data available.


Related in: MedlinePlus