Graphene's featureless optical absorption, ultrahigh carrier mobility, and variable absorption by an applied gate voltage enable a new breed of modulators with broad electrical bandwidths. Here we report on electro-optic modulator that integrates single-layer graphene in sub-wavelength thick, reflective structure. These provide large degree design freedom, which allows tailoring their properties to specific needs. Current devices feature active aperture ~100 µm, uniform modulation flat...

Intracavity loss modulation enables offset-frequency control with bandwidths beyond what is possible by pump power modulation. To demonstrate this new method, we use a subwavelength thick graphene electro-optic modulator to stabilize the offset frequency in Tm:fiber comb at 1.95 μm wavelength. Record-low residual phase noise of 144 mrads was achieved locking scheme.

Surface enhanced Raman spectroscopy (SERS) is a novel method to sense molecular and lattice vibrations at high sensitivity. Although nanostructured silver surface provides intense SERS signals, the unstable under acidic environment heated environment. Graphene, single atomic carbon layer, has prominent stability for chemical agents, its honeycomb completely prevents penetration of small molecules. Here, we fabricated substrate by combining single-crystal monolayer graphene (G-SERS), focused...

Graphene oxide (GO) and reduced GO (RGO) have attracted interest as economical alternatives for pristine graphene with controllable properties spanning their applications in many fields. Abundant lattice defects present RGO made physical chemical largely diverse from that of graphene. This makes identification characterization ambiguous the rules applied may not be practical RGO. Here, we report a new insight into thermally monolayer flakes deposited on different commonly used Si-based...

Abstract Germanene, a 2D honeycomb germanium crystal, is grown at graphene/Ag(111) and hexagonal boron nitride (h‐BN)/Ag(111) interfaces by segregating atoms. A simple annealing process in N 2 or H /Ar ambient pressure leads to the formation of germanene, indicating that an ultrahigh‐vacuum condition not necessary. The germanene stable air uniform over entire area covered with van der Waals (vdW) material. As important finding, it necessary use vdW material as cap layer for present growth...

Manipulation of individual graphene sheets/films into specific architectures at macroscopic scales is crucially important for practical uses graphene. We present herein a versatile and robust method based on annealing solid carbon precursors nickel templates thermo-assisted removal poly(methyl methacrylate) under low vacuum ∼0.6 Pa fabrication macroscopic, freestanding, tubular (TG) architectures. Specifically, the TG can be obtained as woven tubes with diameter ∼50 μm, wall thickness in...

In this Perspective, we present that polariton modes hosted in two-dimensional (2D) materials can be used to increase and control light–matter interactions at the nanoscale. We analyze optical response of most 2D material nanostructures support plasmon, exciton, phonon modes. Polariton characteristic lengths are assess hybrid different monolayers nanoribbons. nanodisk act like a cavity supports localized modes, which excited by nearby placed quantum system ultra-fast ultra-bright operation....

Chemical vapor deposition (CVD) is a promising method of producing large single-crystal graphene on catalyst, especially copper (Cu), and further increase in domain size desirable for electro/optic applications. Here, we report threefold atmospheric-pressure (ATM) annealing suppressing nucleation atmospheric CVD. Threefold ATM formed step terrace surface the underlying Cu, contrast to annealing. Atomic force microscopy Auger electron mapping revealed that Si-containing particles existed...

Fabrication of graphene via oxidation–reduction method is a rewarding approach in terms scalability and cost production. In this regard, restoration the lattice defects presents oxide (GO) during thermal reduction presence carbon source one best alternatives. However, mechanism still unclear. This article ethanol at moderately high temperature by using simple chemical vapor deposition setup, mainly focusing on contribution with increase time to postulate possible mechanism. Raman...

Fabrication of graphene-based transparent conducting films via thermal annealing graphene oxide (GO) is under consideration for commercial mass production as an alternative to high-cost metal oxide-based substrates. Conventional annealing, however, comes with some drawbacks, such high-temperature along longer process times and structural damage that hinders the applicability GO a conductor. Here we report on method fabricating reduced GO-based at low temperature (800 °C) in presence ethanol...

Chemical vapor deposition (CVD) is a promising method to produce large-size single-crystal graphene, and further increase in domain size desirable for electro/optic applications. Here we studied the effect of low amount air introduction by intentional leak on graphene growth atmospheric pressure CVD. The at heating process resulted roughening Cu surface induced oxygen, while annealing under H2 ambient drastically decreased density due reduction active sites nucleation both oxidation...

The effect of hydrogen on the growth carbon nanowalls (CNWs) with different hydrogen-to-carbon (H 2 /CH 4 ) flow ratios in chemical vapor deposition was investigated using scanning electron microscopy (SEM) and Raman spectroscopy. CNWs were synthesized catalyst-free substrates (Si or SiO by microwave plasma-enhanced (MPECVD). At low H rate (0–2), wall size increased increasing ratio while I G / D remained constant; however, at high (2–4), decreased ratios. This indicates that plays roles two...

To exploit the extraordinary property of graphene in practical electrical and optical devices, it is necessary to produce large-sized, single-crystal graphene. Atmospheric pressure chemical vapor deposition (APCVD) on polycrystalline Cu surface a promising scalable route synthesis but unavoidable multiple nucleation limits their reachable domain size. Here, we report that effective suppression was achieved by only turning off hydrogen supply before introduction carbon source for growth. The...

We demonstrate a 500 MHz ultra-low noise 58fs Tm fiber soliton laser based on carrier phase reduction with an electro-optic graphene modulator. The system is used for pumping doubly resonant OP-GaAs OPO coherent mid IR generation.

The effect of hydrogen on the growth carbon nanowalls (CNWs) with different hydrogen-to-carbon (H2/CH4) flow ratios in chemical vapor deposition was investigated using scanning electron microscopy (SEM) and Raman spectroscopy. CNWs were synthesized catalyst-free substrates (Si or SiO2) by microwave plasma-enhanced (MPECVD). At low H2/CH4 rate (0–2), wall size increased increasing ratio while IG/ID remained constant; however, at high (2–4), decreased ratios. This indicates that plays roles...

The deposition of dielectric materials onto graphene without introducing atomic defects is challenging owing to the unavoidable exposure carbon–carbon bonds plasma, energetic ions, or high-energy photons that are present during deposition. Here, we report a simple and nondegradative method depositing silicon oxide layer on based thermal evaporation monoxide (SiO). Raman spectroscopy mapping showed this does not form in graphene, whereas by e-beam severely damages graphene. SiO-coated also...

During the decommissioning of Fukushima Daiichi nuclear power plant, dismantling massive fuel debris is important for defueling process. The production and dispersion radioactive microparticles highly depends on cutting technique implemented. Previous studies have been conducted development techniques treatment particles generation during Besides, adequate understanding microparticle products cuttings vital necessity. Nowadays, geopolymer application proposed as a covering material retrieval...

Poly(lactic acid)/hydroxyapatite (PLA/HAp) core–shell particles are prepared using the emulsification method. These safe for living organisms because they composed of biodegradable polymers and biocompatible ceramics. approximately 50–100 nm in size, their hydrophobic substance loading can be controlled. Hence, PLA/HAp expected to used as drug delivery carriers drugs. In this work, with a vitamin K1 were prepared, drug-loading ability was evaluated. The 40–80 diameter PLA core HAp shell....

Ionic surfactants tend to accumulate in the interfacial region of ultrasonic cavitation bubbles (cavities) because their surface active properties and they are difficult evaporate owing extremely low volatilities. Hence, sonolysis ionic is expected occur cavity. In this study, we performed sonochemical degradation with different charge types: anionic, cationic, zwitterionic, nonionic. We then estimated rates clarify surfactant behavior bubbles. For all investigated, rate increased increasing...

Germanene, a graphene-like single atomic sheet of germanium (Ge), has attracted much attention due to its exotic properties such as tunable bandgaps and high carrier mobility. However, fabrication germanene-based electronic devices is difficult chemical instability. To overcome this, we aim grow germanene at the graphene/metal interface so that can be protected from oxidation in air. Here, study Ge segregation stacked thin film graphene/gold (Au)/silver (Ag)/Ge on silicon substrate...

Based on the fundamental design concept of modulating valence band maximum oxides and subsequent predictions through computational approaches, several lone-pair ns2-based p-type oxide semiconductors, such as Sn2+- or Bi3+-based complex oxides, have been developed. Thus far, bandgap can be modified via tuning chemical composition, whereas hole density cannot intentionally controlled because poor stability Sn2+ and/or formation oxygen vacancies. The inability to control prohibits realization...

Recently, electric double-layer capacitors (EDLCs) have attracted great attention as an energy storage device with high input-output power density. In this study, we synthesized carbon nanotubes (CNTs)/graphite surface area a novel electrode component for EDLC. CNTs were grown on defective graphite by alcohol catalytic chemical vapor deposition the first time. We found that oxidative plasma treatment time attributes to selective growth of laterally-aligned (LA) or vertically-aligned (VA)...

Raman spectroscopy provides a meaningful fingerprint for sensing and discriminating materials, surface-enhanced scattering (SERS) can dramatically increase signals up to the single-molecule level of sensitivity. Graphene, monolayer carbon sheet, has recently attracted considerable attention as unique SERS substrate. However, there are various types graphene application category is significantly correlated structure quality graphene. This review broad perspective on this research area,...