Waveguide Modes in a Planar Graphene–Dielectric Thin-Layer Structure

Particular features of waveguide propagation of modes in a planar structure that consists of alternating layers of a dielectric and graphene are investigated. Within the effective-medium approximation, dispersion relations are obtained for symmetric and antisymmetric waveguide modes. Based on their numerical analysis, the frequency dependences of the propagation and decay constants, of the group and phase velocities, and of the energy flux carried by waveguide modes are constructed. The influence of the fraction of graphene in the structure on the behavior of waveguide modes is analyzed.     

A Novel Pyrene Fluorescent Sensor Based on the π–π Interaction Between Pyrene and Graphene of Graphene–Cadmium Telluride Quantum Dot Nanocomposites

In this article, water-soluble graphene–cadmium telluride quantum dot nanocomposites were fabricated through the synthesis of cadmium telluride quantum dots in the presence of graphene aqueous dispersion. It was found that pyrene could remarkably quench fluorescence of graphene–cadmium telluride quantum dot nanocomposites. On this basis, a novel method for the determination of pyrene was developed. Factors affecting the pyrene detection were investigated, and the optimum conditions were determined. Under the optimum conditions, a linear relationship could be established between the quenching of fluorescence intensity of graphene–cadmium telluride quantum dot nanocomposites and the pyrene concentration in the range of 6.00 × 10^?8–2.00 × 10^?6 mol L^?1 with a correlation coefficient of 0.9959. The detection limit was 4.02 × 10^?8 mol L^?1. Furthermore, the nanocomposites were applied to practical determination of pyrene in different water samples with satisfactory results.     

Graphene译名的一孔之见

乞借贵刊一角,以对石墨烯、富勒烯的译名提出异意,愿与物理学界、化学界、材料科学界学者们切磋之． Graphene名词因发明者A．Geim和K．Novoselov获2010年诺贝尔物理奖而享誉环球．从物理学观点来看,它仅仅是单层或少层石墨片,或者可表述为纯碳原子所构成的石墨单层结构的二维薄膜．它具有特殊的无能隙能带结构,     

溶液法制备Graphene

Graphene因其优异的物理性能和潜在的应用前景,引起物理界和化学界的广泛关注,成为继碳纳米管后凝聚态物理和材料科学领域中又一研究热点,文章详细介绍了近几年发展起来的Graphene的溶液制备方法,例如石墨插层法、液相分散法、氧化石墨还原法、溶剂热法、芳香偶联法等,并对各种方法的特点进行了评述.     

碳化硅表面的外延Graphene

Graphene具有优异的电学性质,是非常有前途的纳米电子材料,有希望替代硅成为下一代集成电路材料,尽管目前有很多种制备Graphene的方法,但就Graphene在将来集成电路方面的应用而言,在碳化硅上的外延生长法最具潜力,文章首先从Graphene的能带结构开始,简单介绍为什么Graphene具有诸多优异的电学性质,比如异常霍尔效应、室温下的高迁移率、碳纳米管的弹道输运等,然后介绍这种外延生长方法及其发展现状,通过比较在不同碳化硅晶面和在不同条件下生长的Graphene的表面形貌,得出结论,在加热炉内,生长在碳化硅晶体碳面的Graphene拥有特别高的质量,最后文章着重讨论对碳面Graphene的电学表征实验,这些实验证明这种材料中的电子是狄拉克电子,同时也发现材料具有优异的电学性质.     

Tunable Bistability in the Goos–H?nchen Effect with Nonlinear Graphene

We present a planar model system of a silica covered with a monolayer of nonlinear graphene to achieve a tunable Goos–H?nchen(GH) shift in the terahertz range. It is theoretically found that the transition between a negative shift and a large positive one can be realized by altering the intensity of incident light. Moreover, by controlling the chemical potential of graphene and the incident angle of light, we can further control the tunable GH shift dynamically. Numerical simulations for GH shifts based on Gaussian waves are in good agreement with our theoretical calculations.     

Graphene Tamm plasmon-induced giant Goos–H?nchen shift at terahertz frequencies

In this Letter, we have shown that a giant Goos–H?nchen shift of a light beam reflected at terahertz frequencies can be achieved by using a composite structure, where monolayer graphene is coated on one-dimensional photonic crystals separated by a dielectric slab. This giant Goos–H?nchen shift originates from the enhancement of the electrical field, owing to the excitation of optical Tamm states at the interface between the graphene and onedimensional photonic crystal. It is shown that the Goos–H?nchen shift in this structure can be significantly enlarged negatively and can be switched from negative to positive due to the tunability of graphene's conductivity. Moreover, the Goos–H?nchen shift of the proposed structure is sensitive to the relaxation time of graphene and the thickness of the top layer, making this structure a good candidate for a dynamic tunable optical shift device in the terahertz regime.     

Spin Polarization Oscillation and Spin-Polarized Diode Based on Graphene Rashba–Strain Double Junctions

We investigate spin-dependent electron transport through graphene-based Rash ba-strain double junctions. It is found that when electrons are injected from left normal graphene region, high spin polarization oscillation is achieved due to the wave-vector-dependent resonant tunneling. The spin polarization is negligible once the incident direction is reversed. Such a remarkable difference arises from pseudogap caused by the Rashba spin-orbit interaction.     

Stone–Wales Bilayer Graphene: Structure,Stability, and Interlayer Heat Transfer

JETP Letters - The structure, stability, and interlayer heat transfer of Stone–Wales bilayer graphene have been studied within a nonorthogonal tight binding model. The most stable...     

Mechanical Properties of Materials Based on Graphene C62H20 and Polyethylene (–CH2–CH2–)n

Technical Physics - The mechanical properties of materials based on graphene C62H20 and polyethylene (–CH2–CH2–)n have been studied using the semiempirical PM3 method, and visual...     

Graphene的制备与结构特性

Graphene是一种严格的二维晶体材料,因其具有独特的结构和性能,已迅速成为国际新材料领域的研究前沿和热点,文章详细介绍了近几年发展起来的Graphene的化学制备方法,如SiC高温热解外延法、过渡金属催化外延法、化学修饰分散/还原法等,并对各种方法的特点,研究现状及应用前景进行了评述.     

Graphene的物理性质与器件应用

Graphene因其新奇的物理性质和广泛的应用前景已迅速成为国际新材料领域的研究前沿和热点.文章详细介绍了Graphene奇特的物理性质(多体相互作用、量子霍尔效应、双极场效应、弱局域化效应等),并对其在微纳米器件、分子电子学、自旋电子学等领域的应用进展给出了综述.     

Graphene Oxide–Carbon Nanotubes Hybrids: Preparation,Characterization, and Application in Phenol Formaldehyde Resin

Graphene oxide–carbon nanotubes hybrids were prepared by using methylene diphenyl diisocyanate as a bridging agent. The as-prepared hybrids were introduced in phenol formaldehyde resin to fabricate polymer-based composites. Fourier transform infrared spectroscopy, transmission electrical microscopy, and X-ray diffraction were performed to characterize the functional groups, morphologies, and crystal structure of the as-prepared hybrids, respectively. The experimental results showed that the carbon nanotubes were loaded on the surfaces of the graphene oxide and they were held together through chemical bonds. Moreover, the as-prepared hybrids could improve the mechanical properties of the matrix. When the as-prepared hybrids loading was 0.6 wt%, the tensile strength, Young's modulus, and elongation at break of the composites were 31.3%, 97.0%, and 75.0% more than the pure sample; in addition, the compression strength and modulus of the composites were 19.7% and 21.3% more than the pure sample, respectively.     

石墨烯（Graphene）的速率记录

内禀电子迁移率（intrinsicelectronmobility）是测定电子在晶格中移动难易程度的一个物理参数，它的单位为cm^2／Vs．它又是使半导体装置能否小型化与快速运行的重要依据、最近由英国Manchester大学G．Gein教授为首的跨国（包括俄罗斯、荷兰和美国）科学家组成的研究组进行了一项极有成效的工作,他们发现二维石墨烯薄层（只有一个原子大小的厚度）半导体的内禀电子迁移率高达200，000cm^2／Vs，这要比硅半导体的内禀电子迁移率（1500cm^2／Vs）高100倍，比砷化镓（8500cm^2／Vs）高20倍。     

Graphene mode-locked femtosecond laser at 2 μm wavelength

We experimentally demonstrated a passively mode-locked femtosecond laser by using a graphene-based saturable absorber mirror (graphene SAM) in the spectral region of 2 μm. The graphene SAM was fabricated by transferring chemical-vapor-deposited, high-quality, and large-area graphene on a highly reflective plane mirror. Stable mode-locked laser pulses as short as 729 fs were obtained with a repetition rate of 98.7 MHz and an average output power of 60.2 mW at 2018 nm.     

Quantum Scars in Microwave Dielec trie Photonic Graphene Billiards

Brillouin zone.The closed graphene system has proven to be the ideal model to investigate relativistic quantum chaos phenomena.The electromagnetic material photonic graphene(PG)and electronic graphene not only have the same structural symmetry,but also have the similar band structure.Thus,we consider a stadium shaped resonant cavity filled with PG to demonstrate the relativistic quantum chaos phenomenon by numerical simulation.It is interesting that the relativistic quantum scars not only are identified in the PG cavities,but also appear and disappear repeatedly.The wave vector difference between repetitive scars on the same orbit is analyzed and confirmed to follow the quantization rule.The exploration will not only demonstrate a visual simulation of relativistic quantum scars but also propose a physical system for observing valley-dependent relativistic quantum scars,which is helpful for further understanding of quantum chaos.     

Graphene integrated photodetectors and opto-electronic devices — a review

Graphene and other two-dimensional materials have recently emerged as promising candidates for next-generation,high-performance photonics. In this paper, the progress of research into photodetectors and other electro-optical devices based on graphene integrated silicon photonics is briefly reviewed. We discuss the performance metrics, photo-response mechanisms, and experimental results of the latest graphene photodetectors integrated with silicon photonics. We also lay out the unavoidable performance trade-offs in meeting the requirements of various applications. In addition, we describe other opto-electronic devices based on this idea. Integrating two-dimensional materials with a silicon platform provides new opportunities in advanced integrated photonics.     

缺陷对Pt在Graphene上吸附影响的研究

本文利用第一原理方法计算了空位缺陷和硼（B）掺杂时对Pt在graphene上吸附的影响.结果表明：Pt在graphene上吸附的稳定位置是Pt吸附在桥位;悬挂键的存在极大的增强了Pt在graphene空位处的吸附;B替位掺杂有利于Pt原子在杂质附近的吸附.     

Features of 30° Moiré Graphene Bilayers with Folded Holes

New nanomeshes with closed holes based on bilayer graphene twisted by 30° are studied. It is found that such structures can have different electronic characteristics (from semiconducting to metallic) depending on the shape of holes. Comparison with the single-layer graphene meshes having holes of similar shapes demonstrates a significant difference of their electronic spectra. The meshes with triangular “folded” holes turn out to be nonmagnetic in contrast to the single-layer meshes with the same holes. The spectra of 30° bilayer graphene nanomeshes exhibit numerous peaks in the electron density of states within a wide energy range. This makes such structures promising for applications in photovoltaics and optoelectronics. Features of 30° Moiré Graphene Bilayers with Folded Holes.