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Full-Text Articles in Engineering
Nonlinear Optical Properties Of Bilayer Graphene In Terahertz Regime, Yee Sin Ang, S Sultan, Rodney Vickers, Chao Zhang
Nonlinear Optical Properties Of Bilayer Graphene In Terahertz Regime, Yee Sin Ang, S Sultan, Rodney Vickers, Chao Zhang
Yee Sin Ang
We have carried out a theoretical and computation study of optical response of bilayer graphene in the terahertz regime. It is found that the optical response of bilayer graphene can be significantly enhanced by nonlinear process for fields greater than 1000v/cm. The optical nonlinearity of bilayer graphene persists even in room temperature. This suggests that bilayer graphene can potentially be utilized as a temperature-robust nonlinear material in the terahertz regime.
Intraband Nonlinear Terahertz Waves Absorption Of Gapped Graphene, Asya Tawfiq, Yee Sin Ang, Chao Zhang
Intraband Nonlinear Terahertz Waves Absorption Of Gapped Graphene, Asya Tawfiq, Yee Sin Ang, Chao Zhang
Yee Sin Ang
The effect of bandgap opening on the intraband nonlinear optical response of graphene in terahertz frequency regime is theoretically investigated. The nonlinear optical response of gapped graphene is found to be sensitively influenced by the bandgap level and temperature. © 2012 IEEE.
Strong Nonlinear Optical Response Of Bilayer Graphene In The Terahertz Regime, Yee Sin Ang, Chao Zhang
Strong Nonlinear Optical Response Of Bilayer Graphene In The Terahertz Regime, Yee Sin Ang, Chao Zhang
Yee Sin Ang
We demonstrate that bilayer graphene exhibits strong nonlinear optical response in the terahertz frequency regime.The electric field strength required to generate single-frequency and triple-frequency nonlinear optical responses comparable to the linear optical response is only moderate and can be easily achieved in laboratory.This strong nonlinear optical response persists even in room temperature.This suggests that bilayer graphene can potentially be utilized in nonlinear terahertz photonics
Two-Color Nonlinear Optical Response Of Graphene With Broken Ab-Symmetry, Yee Sin Ang, Chao Zhang
Two-Color Nonlinear Optical Response Of Graphene With Broken Ab-Symmetry, Yee Sin Ang, Chao Zhang
Yee Sin Ang
We demonstrate that the bandgap opening in graphene induced by AB-sublattice symmetry breaking leads to a strong nonlinear optical response for frequencies well below the bandgap where linear response is strictly forbidden. Our result suggests that one type of graphene with such symmetry breaking, semihydrogenated graphene, can have a unique potential as a two-color nonlinear material in the terahertz photonics.
Quantitative Analysis Of Structure And Bandgap Changes In Graphene Oxide Nanoribbons During Thermal Annealing, Yu Zhu, Xianyu Li, Qinjia Cai, Zhengzong Sun, Gilberto Casillas, Miguel Jose-Yacaman, Rafael Verduzco, James Tour
Quantitative Analysis Of Structure And Bandgap Changes In Graphene Oxide Nanoribbons During Thermal Annealing, Yu Zhu, Xianyu Li, Qinjia Cai, Zhengzong Sun, Gilberto Casillas, Miguel Jose-Yacaman, Rafael Verduzco, James Tour
Yu Zhu
Graphene oxide nanoribbons (GONRs) are wide bandgap semiconductors that can be reduced to metallic graphene nanoribbons. The transformation of GONRs from their semiconductive to the metallic state by annealing has attracted significant interest due to its simplicity. However, the detailed process by which GONRs transform from widebandgap semiconductors to semimetals with a near zero bandgap is unclear. As a result, precise control of the bandgap between these two states is not currently achievable. Here, we quantitatively examine the removal of oxygen-containing groups and changes in the bandgap during thermal annealing of GONRs. X-ray photoelectron spectroscopy measurements show the progressive removal …
A Seemless Three-Dimensional Carbon Nanotube Graphene Hybrid Material, Yu Zhu, Lei Li, Gilberto Casillas, Zhengzong Sun, Zheng Yan, Gedeng Ruan, Zhiwei Peng, Abdul-Rahman Raji, Carter Kittrell, Robert Hauge, James Tour
A Seemless Three-Dimensional Carbon Nanotube Graphene Hybrid Material, Yu Zhu, Lei Li, Gilberto Casillas, Zhengzong Sun, Zheng Yan, Gedeng Ruan, Zhiwei Peng, Abdul-Rahman Raji, Carter Kittrell, Robert Hauge, James Tour
Yu Zhu
Graphene and single-walled carbon nanotubes are carbon materials that exhibit excellent electrical conductivities and large specific surface areas. Theoretical work suggested that a covalently bonded graphene/single-walled carbon nanotube hybrid material would extend those properties to three dimensions, and be useful in energy storage and nanoelectronic technologies. Here we disclose a method to bond graphene and single-walled carbon nanotubes seamlessly during the growth stage. The hybrid material exhibits a surface area 42,000m2 g1 with ohmic contact from the vertically aligned single-walled carbon nanotubes to the graphene. Using aberration-corrected scanning transmission electron microscopy, we observed the covalent transformation of sp2 carbon between …
Flexible Free-Standing Graphene-Silicon Composite Film For Lithium-Ion Batteries, Jiazhao Wang, Chao Zhong, Shulei Chou, Hua Liu
Flexible Free-Standing Graphene-Silicon Composite Film For Lithium-Ion Batteries, Jiazhao Wang, Chao Zhong, Shulei Chou, Hua Liu
Shulei Chou
Flexible, free-standing, paper-like, graphene-silicon composite materials have been synthesized by a simple, one-step, in-situ filtration method. The Si nanoparticles are highly encapsulated in a graphene nanosheet matrix. The electrochemical results show that graphene-Si composite film has much higher discharge capacity beyond 100 cycles (708 mAh g− 1) than that of the cell with pure graphene (304 mAh g− 1). The graphene functions as a flexible mechanical support for strain release, offering an efficient electrically conducting channel, while the nanosized silicon provides the high capacity.