Pub Date : 2021-01-01DOI: 10.1533/9780857099334.2.156
M. Hulman
Abstract: The principles of Raman scattering and the properties of phonons and electrons in graphene are reviewed. The focus is on Raman spectroscopy of mono- and bilayer graphene, particularly perturbations that have a significant influence on the Raman spectra. The distinct behaviour of Raman modes of different orders is discussed.
{"title":"Raman spectroscopy of graphene","authors":"M. Hulman","doi":"10.1533/9780857099334.2.156","DOIUrl":"https://doi.org/10.1533/9780857099334.2.156","url":null,"abstract":"Abstract: The principles of Raman scattering and the properties of phonons and electrons in graphene are reviewed. The focus is on Raman spectroscopy of mono- and bilayer graphene, particularly perturbations that have a significant influence on the Raman spectra. The distinct behaviour of Raman modes of different orders is discussed.","PeriodicalId":63892,"journal":{"name":"石墨烯(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1533/9780857099334.2.156","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67415489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.4236/graphene.2021.103003
Yejin Wu, Kexin Ma, Zhiyong Wang, Xueqiong Dai
{"title":"The Effects of Boron-Doping on the Electronic Properties of Blue Phosphorene","authors":"Yejin Wu, Kexin Ma, Zhiyong Wang, Xueqiong Dai","doi":"10.4236/graphene.2021.103003","DOIUrl":"https://doi.org/10.4236/graphene.2021.103003","url":null,"abstract":"","PeriodicalId":63892,"journal":{"name":"石墨烯(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70614770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.1533/9780857099334.3.228
R. Asgari
Abstract: Electronic transport in bilayer graphene is studied in this chapter and the fundamental physics and conceptual issues are described. A model Hamiltonian system is described and the method for inducing an energy band gap in the system. The transport properties investigated include conductance in a p–n junction, the self-consistent Born approximation and RKKY (Ruderman–Kittel–Kasuya–Yosida) interactions in biased bilayer graphene. Studies on suspended bilayer graphene and on new-generation bilayer graphene samples on SiC are described and the role of many-body effects in these systems is explored. The collective modes in the symmetry and asymmetry charge density channels are discussed and use of the effective mass as an essential quantity in quasiparticle theories is examined. The charge compressibility in bilayer graphene is studied in depth.
{"title":"Electronic transport in bilayer graphene","authors":"R. Asgari","doi":"10.1533/9780857099334.3.228","DOIUrl":"https://doi.org/10.1533/9780857099334.3.228","url":null,"abstract":"Abstract: Electronic transport in bilayer graphene is studied in this chapter and the fundamental physics and conceptual issues are described. A model Hamiltonian system is described and the method for inducing an energy band gap in the system. The transport properties investigated include conductance in a p–n junction, the self-consistent Born approximation and RKKY (Ruderman–Kittel–Kasuya–Yosida) interactions in biased bilayer graphene. Studies on suspended bilayer graphene and on new-generation bilayer graphene samples on SiC are described and the role of many-body effects in these systems is explored. The collective modes in the symmetry and asymmetry charge density channels are discussed and use of the effective mass as an essential quantity in quasiparticle theories is examined. The charge compressibility in bilayer graphene is studied in depth.","PeriodicalId":63892,"journal":{"name":"石墨烯(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1533/9780857099334.3.228","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67415594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.1533/9780857099334.2.124
A. D. Parga, R. Miranda
Abstract: The use of scanning tunneling microscopy and spectroscopy for the characterization of graphene grown or deposited on different substrates is described. The influence of the substrates on the morphology and electronic structure of graphene is discussed. Experimental methods for the characterization of individual defects on the graphene network are described and studies on the fabrication of graphene nanoribbons and examination of the electronic structure of the edges are outlined.
{"title":"Scanning tunneling microscopy (STM) of graphene","authors":"A. D. Parga, R. Miranda","doi":"10.1533/9780857099334.2.124","DOIUrl":"https://doi.org/10.1533/9780857099334.2.124","url":null,"abstract":"Abstract: The use of scanning tunneling microscopy and spectroscopy for the characterization of graphene grown or deposited on different substrates is described. The influence of the substrates on the morphology and electronic structure of graphene is discussed. Experimental methods for the characterization of individual defects on the graphene network are described and studies on the fabrication of graphene nanoribbons and examination of the electronic structure of the edges are outlined.","PeriodicalId":63892,"journal":{"name":"石墨烯(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1533/9780857099334.2.124","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67415941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-09-22DOI: 10.4236/GRAPHENE.2020.91001
M. Al-khateeb, A. A. El-Barbary
Due to rapid depletion of fossil energy sources and increasing the environmental pollution through high fossil energy consumption, an alternative renewable and clean energy carrier as hydrogen is requested more investigations in order to get the optimal request by DOE. In this study, a deepest study on SiC nanocones is done including both of the geometrical and electronic properties of all possible five different disclination angles as a function of size using density functional (DFT) calculations at the B3LYP/6-31g level of theory. Then the hydrogen adsorption mechanism is investigated on three different sites: HS1 (above the first neighbor atom of the apex atoms), HS2 (above one atom of the apex atoms) and HS3 (above one atom far from the apex atoms). Our calculations show that the most candidate SiC nanocone structure for hydrogen storage is Si41N49H10-HS2-M1-Type 2 with disclination angle 300˚. In addition, our results indicate that the hydrogen adsorption induced the energy gap to decrease. Hence, these results indicate that the SiCNCs can be considered as a good candidate for hydrogen storage.
{"title":"Hydrogen Adsorption Mechanism of SiC Nanocones","authors":"M. Al-khateeb, A. A. El-Barbary","doi":"10.4236/GRAPHENE.2020.91001","DOIUrl":"https://doi.org/10.4236/GRAPHENE.2020.91001","url":null,"abstract":"Due to rapid depletion of fossil energy sources and increasing the environmental pollution through high fossil energy consumption, an alternative renewable and clean energy carrier as hydrogen is requested more investigations in order to get the optimal request by DOE. In this study, a deepest study on SiC nanocones is done including both of the geometrical and electronic properties of all possible five different disclination angles as a function of size using density functional (DFT) calculations at the B3LYP/6-31g level of theory. Then the hydrogen adsorption mechanism is investigated on three different sites: HS1 (above the first neighbor atom of the apex atoms), HS2 (above one atom of the apex atoms) and HS3 (above one atom far from the apex atoms). Our calculations show that the most candidate SiC nanocone structure for hydrogen storage is Si41N49H10-HS2-M1-Type 2 with disclination angle 300˚. In addition, our results indicate that the hydrogen adsorption induced the energy gap to decrease. Hence, these results indicate that the SiCNCs can be considered as a good candidate for hydrogen storage.","PeriodicalId":63892,"journal":{"name":"石墨烯(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41706659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-30DOI: 10.4236/graphene.2019.82002
Mingxing Yang, K. Ismoilov, S. Chauhan, Q. Heng, Z. Islamova
The main purpose of this research work is to improve anti-static properties of Cashmere fabric by introducing application comprising anti-static agent by foaming which was made with cationic waterborne polyurethane and graphene-CNC. Cashmere fabric was cut into 10 pieces of sample cloth of 5 cm * 5 cm size, washed with acetone solution, and then dried in an oven at 60℃. Three forms of waterborne polyurethanes such as two forms of Cationic waterborne polyurethane (CWPU) and a form of Anionic waterborne polyurethane (AWPU) were synthesized. Cellulose nanocrystalline (CNC)/graphite powder solution with the ratio of 0.5/1, 1/1, 2/1 was prepared by ultrasonic probe stripping method, and the concentration of graphite powder was ensured to be 1 mg/ml. The fabric was treated with anionic and cationic WPUs foaming solution until the weight gain reached 2.5 - 3.5 wt%. After drying, the elastic cloth was foamed with graphene solution until the graphite content of the cloth was close to 10%, 20%, 40%, 60% respectively, and then dried for reserving. Characterization properties of pure graphite powder, pure CNC and graphene solution with different proportions of three components were tested by Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD), Thermalgravitimetric analysis (TGA) and scanning electron microscopy (SEM). Take the original cloth, only WPU treated cloth and four clothes with different graphite content for the fabric performance test.
{"title":"Preparation and Application of Anionic and Cationic Waterborne Polyurethanes and Graphene-Cellulose Nanocrystal as an Antistatic Agent for Cashmere","authors":"Mingxing Yang, K. Ismoilov, S. Chauhan, Q. Heng, Z. Islamova","doi":"10.4236/graphene.2019.82002","DOIUrl":"https://doi.org/10.4236/graphene.2019.82002","url":null,"abstract":"The main purpose of this research work is to improve anti-static properties of Cashmere fabric by introducing application comprising anti-static agent by foaming which was made with cationic waterborne polyurethane and graphene-CNC. Cashmere fabric was cut into 10 pieces of sample cloth of 5 cm * 5 cm size, washed with acetone solution, and then dried in an oven at 60℃. Three forms of waterborne polyurethanes such as two forms of Cationic waterborne polyurethane (CWPU) and a form of Anionic waterborne polyurethane (AWPU) were synthesized. Cellulose nanocrystalline (CNC)/graphite powder solution with the ratio of 0.5/1, 1/1, 2/1 was prepared by ultrasonic probe stripping method, and the concentration of graphite powder was ensured to be 1 mg/ml. The fabric was treated with anionic and cationic WPUs foaming solution until the weight gain reached 2.5 - 3.5 wt%. After drying, the elastic cloth was foamed with graphene solution until the graphite content of the cloth was close to 10%, 20%, 40%, 60% respectively, and then dried for reserving. Characterization properties of pure graphite powder, pure CNC and graphene solution with different proportions of three components were tested by Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD), Thermalgravitimetric analysis (TGA) and scanning electron microscopy (SEM). Take the original cloth, only WPU treated cloth and four clothes with different graphite content for the fabric performance test.","PeriodicalId":63892,"journal":{"name":"石墨烯(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48281475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-23DOI: 10.4236/GRAPHENE.2019.81001
R. Holt, T. Rybolt
The possibility of a graphene bilayer nanosensor for the detection of explosive molecules was modeled using computational chemistry. A pore was designed on a graphene bilayer structure with three strategically placed perimeter hydroxyl (OH) groups built around the edge of an indented, two-dimensional hexagonal pore. This hydroxylated pore and models of various explosive molecules were optimized using MM2 molecular mechanics parameters. Values were calculated for the molecule-surface interaction energy (binding energy), E, for 22 explosive molecules on a flat graphene bilayer and on the specially designed hydroxylated pore within the bilayer. The molecule-surface binding energy for trinitrotoluene (TNT) increased from 17.9 kcal/mol on the flat graphene bilayer to 42.3 kcal/mol on the hydroxylated pore. Due to the common functionality of nitro groups that exist on many explosive molecules, the other explosive molecules studied gave similar enhancements based on the specific hydrogen bonding interactions formed within the pore. Each of the 22 explosive adsorbate molecules showed increased molecule-surface interaction on the bilayer hydroxylated pore as compared to the flat bilayer. For the 22 molecules, the average E for the flat graphite surface was 15.8 kcal/mol and for the hydroxylated pore E was 33.8 kcal/mol. An enhancement of adsorption should make a detection device more sensitive. Nanosensors based on a modified graphene surface may be useful for detecting extremely low concentrations of explosive molecules or explosive signature molecules.
{"title":"Modeling Enhanced Adsorption of Explosive Molecules on a Hydroxylated Graphene Pore","authors":"R. Holt, T. Rybolt","doi":"10.4236/GRAPHENE.2019.81001","DOIUrl":"https://doi.org/10.4236/GRAPHENE.2019.81001","url":null,"abstract":"The possibility of a graphene bilayer nanosensor for the detection of explosive molecules was modeled using computational chemistry. A pore was designed on a graphene bilayer structure with three strategically placed perimeter hydroxyl (OH) groups built around the edge of an indented, two-dimensional hexagonal pore. This hydroxylated pore and models of various explosive molecules were optimized using MM2 molecular mechanics parameters. Values were calculated for the molecule-surface interaction energy (binding energy), E, for 22 explosive molecules on a flat graphene bilayer and on the specially designed hydroxylated pore within the bilayer. The molecule-surface binding energy for trinitrotoluene (TNT) increased from 17.9 kcal/mol on the flat graphene bilayer to 42.3 kcal/mol on the hydroxylated pore. Due to the common functionality of nitro groups that exist on many explosive molecules, the other explosive molecules studied gave similar enhancements based on the specific hydrogen bonding interactions formed within the pore. Each of the 22 explosive adsorbate molecules showed increased molecule-surface interaction on the bilayer hydroxylated pore as compared to the flat bilayer. For the 22 molecules, the average E for the flat graphite surface was 15.8 kcal/mol and for the hydroxylated pore E was 33.8 kcal/mol. An enhancement of adsorption should make a detection device more sensitive. Nanosensors based on a modified graphene surface may be useful for detecting extremely low concentrations of explosive molecules or explosive signature molecules.","PeriodicalId":63892,"journal":{"name":"石墨烯(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41888175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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