The thermal properties of a suspended metallic single-wall carbon nanotube (SWNT) are extracted from its high-bias (I-V) electrical characteristics over the 300-800 K temperature range, achieved by Joule self-heating. conductance is approximately 2.4 nW/K and conductivity nearly 3500 W/m/K at room for SWNT length 2.6 um diameter 1.7 nm. A subtle decrease in steeper than 1/T observed upper end which attributed to second order three-phonon scattering between two acoustic modes one optical...

Significance Carbon has many faces––from diamond and graphite to graphene, nanotube, fullerenes. Whereas hexagons are the primary building blocks of these materials, except for C 20 fullerene, carbon structures made exclusively pentagons not known. Because exotic properties associated with their unique structures, some fundamental questions arise: Is it possible have materials if so will they be stable unusual properties? Based on extensive analyses simulations we show that penta-graphene,...

Arrays of electrical devices with each comprising multiple single-walled carbon nanotubes (SWNT) bridging metal electrodes are obtained by chemical vapor deposition (CVD) across prefabricated electrode arrays. The ensemble in such a device collectively exhibits large conductance changes under electrostatic gating, owing to the high percentage semiconducting nanotubes. This leads fabrication arrays low-noise nanotube sensors 100% yield for detecting gas molecules. Polymer functionalization is...

Carbon nanotube field-effect transistors commonly comprise nanotubes lying on SiO2 surfaces exposed to the ambient environment. It is shown here that exhibit hysteresis in their electrical characteristics because of charge trapping by water molecules around nanotubes, including surface-bound proximal nanotubes. Hysteresis persists for vacuum since SiO2-bound does not completely desorb at room temperature, a known phenomenon surface chemistry. Heating under dry conditions significantly...

Single layer of graphite (graphene) was predicted and later experimentally confirmed to undergo metal-semiconductor transition when fully hydrogenated (graphane). Using density functional theory we show that half the hydrogen in this graphane sheet is removed, resulting semihydrogenated graphene (which refer as graphone) becomes a ferromagnetic semiconductor with small indirect gap. Half-hydrogenation breaks delocalized pi bonding network graphene, leaving electrons unhydrogenated carbon...

Recent efforts in finding materials suitable for storing hydrogen with large gravimetric density have focused attention on carbon-based nanostructures. Unfortunately, pure carbon nanotubes and fullerenes are unsuitable as storage because of the weak bonding molecules to frame. It has been shown very recently that coating nanostructures isolated transition metal atoms such Sc Ti can increase binding energy lead high capacity (up 8 wt % hydrogen, which is 1.6 times U.S. Department Energy...

Single walled carbon nanotubes with Pd Ohmic contacts and lengths ranging from several microns down to 10 nm are investigated by electron transport experiments theory. The mean-free path (MFP) for acoustic phonon scattering is estimated be ${l}_{\mathrm{ap}}\ensuremath{\sim}300\text{ }\text{ }\mathrm{nm}$, that optical ${l}_{\mathrm{op}}\ensuremath{\sim}15\text{ }\mathrm{nm}$. Transport through very short ($\ensuremath{\sim}10\text{ }\mathrm{nm}$) free of significant thus ballistic...

Solid state materials capable of storing hydrogen with high gravimetric (9 wt %) and volumetric density (70 g/L) are critical for the success a new economy. In addition, an ideal storage system should be able to operate under ambient thermodynamic conditions exhibit fast sorption kinetics. No known that meet all these requirements. While recent theoretical efforts showed some promise transition-metal-coated carbon fullerenes, later studies demonstrated metal atoms prefer cluster on fullerene...

Single-walled carbon nanotubes (SWNT) are grown by a plasma enhanced chemical vapor deposition (PECVD) method at 600 °C. The of high quality as characterized microscopy, Raman spectroscopy, and electrical transport measurements. High performance field effect transistors obtained with the PECVD nanotubes. Interestingly, characterization reveals that nearly 90% semiconductors thus highly preferential growth semiconducting over metallic tubes in process. Control experiments other nanotube...

An electromechanical system is constructed to explore the electrical properties of various types suspended single-walled carbon nanotubes under influence tensile stretching. Small band-gap semiconducting (or quasimetallic) exhibit largest resistance changes and piezoresistive gauge factors ( approximately 600 1000) axial strains. Metallic much weaker but nonzero sensitivity. Comparison between experiments theoretical predictions potential applications nanotube systems for physical sensors...

Abstract Potassium‐ion batteries (KIBs) are very promising alternatives to lithium‐ion (LIBs) for large‐scale energy storage. However, traditional carbon anode materials usually show poor performance in KIBs due the large size of K ions. Herein, a carbonization‐etching strategy is reported making class sulfur (S) and oxygen (O) codoped porous hard microspheres (PCMs) material as novel through pyrolysis polymer (PMs) composed liquid crystal/epoxy monomer/thiol hardener system. The as‐made...

Single-crystal Ge nanowires are synthesized by a low-temperature (275 °C) chemical vapor deposition (CVD) method. Boron doped p-type GeNW field-effect transistors (FETs) with back-gates and thin SiO2 (10 nm) gate insulators constructed. Hole mobility higher than 600 cm2/V s is observed in these devices, suggesting high quality excellent electrical properties of as-grown wires. In addition, integration high-κ HfO2 (12 dielectric into nanowire FETs top-gates accomplished promising device...

An oxygen assisted hydrocarbon chemical vapor deposition (CVD) method is developed to afford large-scale highly reproducible ultra high-yield growth of vertical single-walled carbon nanotubes (SWNT). It revealed that reactive hydrogen (H)-species, inevitable in hydrocarbon-based growth, are damaging the formation sp2-like SWNTs. The addition scavenges H-species and provides a powerful control over C/H ratio favor SWNT growth. revelation roles played by leads unified universal optimum...

Extensive calculations based on density functional theory have been carried out to understand the origin of magnetism in undoped ZnO thin films as found recent experiments. The observed is confirmed be due Zn, instead O, vacancy. main source magnetic moment, however, arises from unpaired $2p$ electrons at O sites surrounding Zn vacancy with each nearest-neighbor atom carrying a moment ranging...

Freely suspended metallic single-walled carbon nanotubes (SWNTs) exhibit reduced current carrying ability compared to those lying on substrates, and striking negative differential conductance at low electric fields. Theoretical analysis reveals significant self-heating effects including electron scattering by hot nonequilibrium optical phonons. Electron transport characteristics under strong are exploited for the first time probe thermal conductivity of individual SWNTs (approximately 3600 W...

Contacting metallic single-walled carbon nanotubes by palladium (Pd) affords highly reproducible ohmic contacts and allows for detailed elucidation of ballistic transport in nanotubes. The Pd are more reliable than titanium (Ti) previously used nanotube devices. In contrast, Pt appear to give non-ohmic For both contacts, the length under metal contact area is electrically turned off. Transport occurs from at edges contacts. Measurements with large numbers contacted samples reveal that mean...

Ti3C2Tx, a 2D titanium carbide in the MXenes family, is obtained from Ti3AlC2 through selective etching of Al layer. Due to its good conductivity and high volumetric capacitance, Ti3C2Tx regarded as promising candidate for supercapacitors. In this paper, fabrication Ti3C2Tx/RGO composites with different proportions RGO reported, which acts conductive "bridge" connect blocks matrix alleviate volume change during charge/discharge process. addition, nanosheets can serve second nanoscale current...

First principles calculations based on density functional theory reveal some unusual properties of BN sheet functionalized with hydrogen and fluorine. These differ from those similarly graphene even though both share the same honeycomb structure. (1) Unlike which undergoes a metal to insulator transition when fully hydrogenated, band gap significantly narrows saturated hydrogen. Furthermore, can be tuned 4.7 eV 0.6 system direct or an indirect semiconductor half-metal depending upon surface...

Motivated by the recent study of inspiring thermoelectric properties in bulk SnSe [Zhao et al., Nature, 2014, 508, 373] and experimental synthesis sheets [Chen J. Am. Chem. Soc., 2013, 135, 1213], we have carried out systematic calculations for a single-layered sheet focusing on its stability, electronic structure using density functional theory combined with Boltzmann transport theory. We found that is dynamically thermally stable band gap 1.28 eV, figure merit (ZT) reaches 3.27 (2.76)...

Using density functional theory, we show that an applied electric field can substantially improve the hydrogen storage properties of polarizable substrates. This new concept is demonstrated by adsorbing a layer molecules on number nanomaterials. When one H(2) adsorbed BN sheet, binding energy per molecule increases from 0.03 eV/H(2) in field-free case to 0.14 presence 0.045 a.u. The corresponding gravimetric 7.5 wt% consistent with 6 system target set Department Energy for 2010. strength be...

Using state-of-the-art first-principles calculations, we propose a new two-dimensional (2D) carbon allotrope constructed by polymerizing the skeletons of s-indacenes, named PSI (ψ)-graphene. We show that ψ-graphene has lowest energy among all hitherto reported 2D allotropes composed 5-6-7 rings and is dynamically thermally stable. This structure metallic with robust metallicity against external strain. In addition, find adsorption Li atoms on exothermic, diffusion barrier low comparable to...

Lithium-metal batteries (LMBs) with high energy densities are highly desirable for storage, but generally suffer from dendrite growth and side reactions in liquid electrolytes; thus the need solid electrolytes mechanical strength, ionic conductivity, compatible interface arises. Herein, a thiol-branched polymer electrolyte (SPE) is introduced featuring Li+ conductivity (2.26 × 10-4 S cm-1 at room temperature) good strength (9.4 MPa)/toughness (≈500%), unblocking tradeoff between robustness...