Quantum confinement effect in armchair graphene nanoribbons: Effect of strain on band gap modulation studied using first-principles calculations

Loh, Siow Mean; Huang, Yuhui; Lin, Ken-Ming; Su, Wan-Sheng; Wu, Bi-Ru; Leung, T. C.

doi:10.1103/physrevb.90.035450

Cited by 15 publications

(7 citation statements)

References 37 publications

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“…For example, the | E c | value is 0.6 V/Å for N a = 7, whereas it decreases to 0.3 V/Å for N a = 18. This phenomenon occurs because a smaller NR width induces a larger separation between the conduction band and the valence band levels due to greater quantum confinement . Such band gap behavior satisfies the condition proposed by Sanvito et al, confirming that the | E c | value required for band gap closure is inversely proportional to the NR width (Figure c).…”

Section: Resultssupporting

confidence: 81%

“…This phenomenon occurs because a smaller NR width induces a larger separation between the conduction band and the valence band levels due to greater quantum confinement. 45 Such band gap behavior satisfies the condition proposed by Sanvito et al, 14 confirming that the |E c | value required for band gap closure is inversely proportional to the NR width ( Figure 2c). Interestingly, we further observed that across the entire electric field range examined in this study, the band gap nature is direct at the Γ point until it vanishes.…”

Section: ■ Results and Discussionsupporting

confidence: 80%

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Modulating Electronic Structures of Armchair GaN Nanoribbons by Chemical Functionalization under an Electric Field Effect

Alaal

Roqan

2020

ACS Omega

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The electronic and magnetic properties of oxygen-and sulfur-passivated one-dimensional armchair GaN nanoribbons (A-GaNNRs) are revealed using both firstprinciples density-functional theory and ab initio molecular dynamics simulations. We explore that an applied external electric field can further modulate the electronic properties of both pristine and passivated A-GaNNRs, thus changing their properties (semiconducting−metallic−half-metallic). A-GaNNRs of 0.9−3.1 nm width are subjected to further investigations, which reveal that sulfur termination transforms pristine A-GaNNRs from direct into indirect band gap semiconductors, without affecting their nonmagnetic nature. On the other hand, oxygen passivation introduces spin-polarized behavior with a finite magnetic moment. Magnetism characteristics in both bare and sulfur-passivated A-GaNNRs are induced by applying a critical electric field along the direction of NR width. The passivated A-GaNNRs are more stable compared to bare ones, while sulfur-passivated A-GaNNRs exhibit higher stability at higher temperatures (>500°C). Thus, our results suggest that A-GaNNRs can be used in a broad range of electronic, optoelectronic, and spintronic applications.

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Section: Resultssupporting

confidence: 81%

Section: ■ Results and Discussionsupporting

confidence: 80%

Modulating Electronic Structures of Armchair GaN Nanoribbons by Chemical Functionalization under an Electric Field Effect

Alaal

Roqan

2020

ACS Omega

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“…Besides an external electric field, the distortions and defects of the ZGNR are also predicted to have an effect on band structures 20-21 . Furthermore, doping with various types of foreign atoms, adsorption of foreign atoms or molecules and external stress are other effective ways to widen their possible applications [22][23][24] .…”

Section: Introductionmentioning

confidence: 99%

Screening effects on the field enhancement factor of zigzag graphene nanoribbon arrays: a first-principles study

Lin

Leung

et al. 2018

Phys. Chem. Chem. Phys.

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The field screening effect on the electronic and field-emission properties of zigzag graphene nanoribbons (ZGNRs) has been studied using first-principles calculations. We have systematically investigated the effects of inter-ribbon distance and ribbon width on the work function, field enhancement factor, band gap and edge magnetism of zigzag graphene nanoribbons (ZGNRs). It is found that the work function of ZGNRs increases rapidly as the inter-ribbon distance Dx increases, which is caused by the positive dipole at the edge of the ribbon. For a given Dx, the work function of ZGNRs decreases as the ribbon width W increases. The wider the ribbon, the stronger the effect of inter-ribbon distance on the work function. Using a simple linear interpolation model, we can obtain the work function of ZGNRs of any ribbon-width. In the case of Dx < W, the field enhancement factor increases rapidly as the inter-ribbon distance increases. As we further increase Dx, the enhancement factor increases slowly and then tends toward saturation. The inter-ribbon distance of ZGNRs can modulate the magnitude of the band gap and edge magnetism. These observations can all be explained by the screening effect.

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“…The change of work function induced by a passivation or adsorbates can be attributed to the barrier of surface dipoles and Fermi level shifts. In previous study, 19 it was found the shift of the Fermi energy relative to the vacuum level is caused by the asymmetry of the slope of the Dirac cone, represented as …”

Section: Resultsmentioning

confidence: 99%

“… 17,18 Although there are several methods to tune the band gap of AGNR, one effective way is applying an external stress. 19–21 Recently, the relation between inversion symmetry breaking and gap opening has been studied, 22,23 for instance, asymmetrical strain distributions notably adjust the band structure near the Fermi energy of graphene. 24 Furthermore, graphene can be used as an active channel layer.…”

Section: Introductionmentioning

confidence: 99%

Strain and screening effects on field emission properties of armchair graphene nanoribbon arrays: a first-principles study

Loh

Leung

et al. 2018

RSC Adv.

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Quantum confinement effect in armchair graphene nanoribbons: Effect of strain on band gap modulation studied using first-principles calculations

Cited by 15 publications

References 37 publications

Modulating Electronic Structures of Armchair GaN Nanoribbons by Chemical Functionalization under an Electric Field Effect

Modulating Electronic Structures of Armchair GaN Nanoribbons by Chemical Functionalization under an Electric Field Effect

Screening effects on the field enhancement factor of zigzag graphene nanoribbon arrays: a first-principles study

Strain and screening effects on field emission properties of armchair graphene nanoribbon arrays: a first-principles study

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