Theoretical Study of Heterojunction-Like Electronic Properties Between a Semiconductive Graphene Nanoribbon and a Metallic Graphene for Highly Sensitive Strain Sensors

2020 ◽  
Author(s):  
Qinqiang Zhang ◽  
Xiangyu Qiao ◽  
Masasuke Kobayashi ◽  
Ken Suzuki
Keyword(s):  
Electronic Properties ◽  
Ohmic Contact ◽  
Electronic Band Structure ◽  
Graphene Nanoribbons ◽  
Electron Flow ◽  
Strain Sensors ◽  
Sensitive Strain ◽  
Sensing Element ◽  
Electronic Band ◽  
Highly Sensitive

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.

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

2018 ◽  
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.

scholarly journals Development of Highly Sensitive Strain Sensor Using Area-Arrayed Graphene Nanoribbons

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1701
Author(s):  
Ken Suzuki ◽  
Ryohei Nakagawa ◽  
Qinqiang Zhang ◽  
Hideo Miura
Keyword(s):  
Graphene Nanoribbons ◽  
Strain Sensor ◽  
Strain Sensors ◽  
Sensitive Strain ◽  
Bending Test ◽  
Gauge Factor ◽  
Four Point Bending ◽  
Current Voltage ◽  
Highly Sensitive ◽  
Current Voltage Relationship

In this study, a basic design of area-arrayed graphene nanoribbon (GNR) strain sensors was proposed to realize the next generation of strain sensors. To fabricate the area-arrayed GNRs, a top-down approach was employed, in which GNRs were cut out from a large graphene sheet using an electron beam lithography technique. GNRs with widths of 400 nm, 300 nm, 200 nm, and 50 nm were fabricated, and their current-voltage characteristics were evaluated. The current values of GNRs with widths of 200 nm and above increased linearly with increasing applied voltage, indicating that these GNRs were metallic conductors and a good ohmic junction was formed between graphene and the electrode. There were two types of GNRs with a width of 50 nm, one with a linear current–voltage relationship and the other with a nonlinear one. We evaluated the strain sensitivity of the 50 nm GNR exhibiting metallic conduction by applying a four-point bending test, and found that the gauge factor of this GNR was about 50. Thus, GNRs with a width of about 50 nm can be used to realize a highly sensitive strain sensor.

First Principle Analysis of the Effect of Strain on Electronic Transport Properties of Dumbbell-Shape Graphene Nanoribbons

2019 ◽  
Author(s):  
Takuya Kudo ◽  
Qinqiang Zhang ◽  
Ken Suzuki ◽  
Hideo Miura
Keyword(s):  
High Performance ◽  
Density Functional ◽  
Graphene Nanoribbons ◽  
Strain Sensor ◽  
Strain Sensors ◽  
First Principle ◽  
Next Generation ◽  
Electronic Band ◽  
Nano Scale ◽  
Highly Sensitive

Abstract Graphene nanoribbons (GNRs), nano scale strips of graphene which consists of carbon hexagonal unit cell, are expected as next generation materials for high performance devices because of its unique super-conductive properties. When the strip width of graphene is cut into nano-scale, thinner than 70 nm, however, band gap starts to appear in the thin GNRs at room temperature, and thus, they show semiconductive properties. Previous studies have shown that the bad gap of GNR is highly sensitive to strain, which indicates that GNRs are candidates for a detective element of highly sensitive strain sensors. In practical applications, ohmic contact between a metallic electrode and a semiconductive detective element is indispensable for these sensors. By considering the effect of the width of GNRs on their electronic properties, dumbbell-shape GNRs (DS-GNRs) structures have been proposed for the basic structure of the GNR-base strain sensors, which consisted of GNRs with two different widths. Center portion of the DS-GNR is narrower than 70 nm and GNRs wider than 70 nm are attached at the both ends of the center GNR as electrode. Both semiconductive and metallic portions of a strain sensor consist of only carbon atoms using this DS-GNR structure. Even though this structure consists of one material, the effect of the interaction between two metallic and semiconductive GNRs must be clarified to realize the strain sensor with high performance. In this study, first principle calculations were applied to the analysis of the electronic band structure of the DS-GNR based on density functional theory (DFT). It was found that the local distribution of energy states of electrons and charges varied drastically as strong functions of the length of GNRs and the magnitude of the applied strain. The current through the DS-GNR structure was converged as the length of the semiconductive portion increased. In the models with enough length, transport property of the DS-GNR showed high sensitivity to strain. Thus, the effective resistivity of the structure varied from metallic to semiconductive, and therefore, this structure is appropriate for the next-generation highly sensitive and deformable strain sensors.

scholarly journals Crack-induced Ag nanowire networks for transparent, stretchable, and highly sensitive strain sensors

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Chan-Jae Lee ◽  
Keum Hwan Park ◽  
Chul Jong Han ◽  
Min Suk Oh ◽  
Banseok You ◽  
...  
Keyword(s):  
Strain Sensors ◽  
Sensitive Strain ◽  
Highly Sensitive ◽  
Nanowire Networks ◽  
Ag Nanowire

Highly sensitive strain sensors based on fragmentized carbon nanotube/polydimethylsiloxane composites

2018 ◽  
Vol 29 (23) ◽  
pp. 235501 ◽  
Author(s):  
Yang Gao ◽  
Xiaoliang Fang ◽  
Jianping Tan ◽  
Ting Lu ◽  
Likun Pan ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Strain Sensors ◽  
Sensitive Strain ◽  
Highly Sensitive

Flexible resistance-type strain sensors toward monitoring finger movements

Synlett ◽  
2021 ◽  
Author(s):  
Chao Lu ◽  
Xi Chen
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Properties ◽  
Composite Films ◽  
Strain Sensors ◽  
Sensitive Strain ◽  
Nanocomposite Films ◽  
Finger Movements ◽  
Resistance Response ◽  
Mechanical And Electrical Properties ◽  
Highly Sensitive

Flexible strain sensors with superior flexibility and high sensitivity are critical to artificial intelligence. And it is favorable to develop highly sensitive strain sensors with simple and cost effective method. Here, we have prepared carbon nanotubes enhanced thermal polyurethane nanocomposites with good mechanical and electrical properties for fabrication of highly sensitive strain sensors. The nanomaterials have been prepared through simple but effective solvent evaporation method, and the cheap polyurethane has been utilized as main raw materials. Only a small quantity of carbon nanotubes with mass content of 5% has been doped into polyurethane matrix with purpose of enhancing mechanical and electrical properties of the nanocomposites. As a result, the flexible nanocomposite films present highly sensitive resistance response under external strain stimulus. The strain sensors based on these flexible composite films deliver excellent sensitivity and conformality under mechanical conditions, and detect finger movements precisely under different bending angles.

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