Theoretical Study of Electronic Band Structure of Dumbbell-Shape Graphene Nanoribbons for Highly-sensitive and Stable Strain Sensors

Abstract Graphene shows unique super-conductive properties and graphene nanoribbons (GNRs) with band gaps are the candidates for a sensing component of highly sensitive strain sensors. Usually, there is a large energy barrier between electrodes and semiconductors which is not suitable for electron transfer. Therefore, ohmic contact between them is indispensable for fabricating electronic applications. In order to achieve the ohmic contact between external electrodes and detective elements in the devices, the dumbbell-shaped structure of GNRs was proposed for the basic structure of the GNR-based strain sensors, dubbed as dumbbell-shape GNR (DS-GNR). It consists of a long narrow GNR at the center of the structure as the sensing element coalesced with two wider GNRs at both ends of the narrow GNR as the contact components to external electrodes. Both narrow and wide segments of DS-GNR consist of only carbon atoms. The effect of the interaction in the vicinity of the junction area between wide metallic and narrow semiconductive GNRs, however, has not been clearly demonstrated. In this study, first-principles calculations were implemented to the analysis of the electronic band structure of the DS-GNR. It was found that the localized distribution of the energy states of electrons exists in the wide segment of DS-GNR. The changes varied from wide to narrow segment is smooth and observable as strong functions of the length and the width of DS-GNRs. The current-voltage characteristics showed curved semiconductive-like electronic properties with a smooth-electron flow in DS-GNR. Therefore, the DS-GNR has great potential for the use of next-generation highly sensitive and deformable strain sensors.

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Theoretical Study of Electronic Band Structure of Dumbbell-Shape Graphene Nanoribbons for Highly-Sensitive Strain Sensors

Volume 10: Micro- and Nano-Systems Engineering and Packaging ◽

10.1115/imece2018-88431 ◽

2018 ◽

Cited By ~ 1

Author(s):

Qinqiang Zhang ◽

Takuya Kudo ◽

Ken Suzuki

Keyword(s):

Band Structure ◽

Band Gap ◽

Electronic Band Structure ◽

Molecular Orbitals ◽

Strain Sensors ◽

Sensitive Strain ◽

Electronic Band ◽

Narrow Part ◽

Highly Sensitive ◽

Shape Structure

The authors have proposed the formation of dumbbell-shape graphene nanoribbon (GNR) for developing various semi-conductive materials with metallic electrode at both ends. The novel dumbbell-shape structure, which has a center narrow part and wide parts to sandwich the narrow part, can be considered as a composite structure consisting of two single GNRs with different ribbon width. In this study, the electronic band structure of this dumbbell-shape GNR was analyzed by using the first principle calculation method. All the first-principles calculations were performed using DFT. Throughout these calculations, the electronic band structures, densities of states, and orbital distributions of the new dumbbell-shape structure GNR were examined to describe the electronic properties of dumbbell-shape GNRs and predict the performance of strain sensors. The band gap of dumbbell-shape GNRs is different to that of single GNRs. The magnitude of the band gap of the dumbbell-shape GNR depends on the combination of the single GNRs and the difference in the width of narrow part and wide parts. The main change to the band gap is attributed to a change in the orbital distributions of the lowest unoccupied molecular orbitals (LUMO) and the highest occupied molecular orbitals (HOMO). In addition, when a dumbbell-shape GNR undergoes a uniaxial tensile strain, its band gap showed high strain sensitivity as was expected. Therefore, the GNR material with a dumbbell-shape structure has great potential for use in highly sensitive strain sensors.

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Theoretical Study of L-Edge Resonant Inelastic X-ray Scattering in La2CuO4 on the Basis of Detailed Electronic Band Structure

Journal of the Physical Society of Japan ◽

10.7566/jpsj.84.094704 ◽

2015 ◽

Vol 84 (9) ◽

pp. 094704 ◽

Cited By ~ 3

Author(s):

Takuji Nomura

Keyword(s):

Band Structure ◽

Theoretical Study ◽

Electronic Band Structure ◽

Electronic Band ◽

X Ray ◽

X Ray Scattering ◽

Ray Scattering

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Highly Sensitive Strain Sensor Using Dumbbell-Shape Graphene Nanoribbon

Volume 10: Micro- and Nano-Systems Engineering and Packaging ◽

10.1115/imece2017-70318 ◽

2017 ◽

Author(s):

Qinqiang Zhang ◽

Meng Yang ◽

Ken Suzuki ◽

Hideo Miura

Keyword(s):

Band Structure ◽

Band Gap ◽

First Principles ◽

Room Temperature ◽

Electronic Band Structure ◽

Strain Sensor ◽

Uniaxial Strain ◽

First Principles Calculations ◽

Electronic Band ◽

Highly Sensitive

A nano-scale strip of graphene is known as graphene nano-ribbon (GNR). Previous studies have shown that the armchair-type GNR (aGNR) can open the electronic band gap at room temperature, and the band gap increases monotonically with the decrease in the width of aGNR. The critical width at which aGNR shows semi-conductive characteristics at room temperature is about 70 nm, when it is passivated by hydrogen on both sides. However, the electronic band structure varies frequently as a function of the number of carbon atoms along its width direction. In order to decrease the large variation of the band gap of aGNR to control the electronic properties of GNR for highly sensitive sensors and high performance devices, the electronic band structure of various dumbbell-shape structure of aGNR was analyzed by first-principles calculations based on the density functional theory using implemented in SIESTA package. It was shown that the width of aGNR had a large effect on the electronic band structure and the amplitude of the fluctuation of the band gap as a function of the number of carbon atoms decreased drastically. The electronic band structure of various GNRs under the application of uniaxial strain was also analyzed by using the first-principles calculations, in this study. It was confirmed that the effective band gap of aGNR thinner than 70 nm varies drastically under the application of uniaxial strain, and this result clearly indicates the possibility of a highly sensitive strain sensor using dumbbell-shape GNR structures.

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