Dimension-and lattice-diversified Coulomb excitations in3D,2D,1D-nanotube electron gases,graphene and carbon nanotube

填充温室气体的碳纳米管的力学与吸附特性

Mechanical and adsorption properties of greenhouse gases filled carbon nanotubes

本研究通过GCMC和MD模拟探究填充温室气体的单壁碳纳米管的力学与吸附特性，发现其可有效分离CO₂与CH₄，且填充气体对压缩力学性能有复杂影响，锯齿型管力学表现更优。

Thermally and Molecularly Stimulated Relaxation of Hot Phonons in Suspended Carbon Nanotubes

The high-bias electrical transport properties of suspended metallic single-walled carbon nanotubes (SWNTs) are investigated at various temperatures in vacuum, in various gases and when coated with molecular solids. It is revealed that non-equilibrium optical phonon effects in suspended nanotubes decrease as the ambient temperature increases. Gas molecules surrounding suspended SWNTs assist the relaxation of hot phonons and afford enhanced current flow along nanotubes. Molecular solids of carbon dioxide frozen onto suspended SWNTs quench the non-equilibrium phonon effect. The discovery of stron…

Bipolar single-wall carbon nanotube field-effect transistor

We use a simultaneous flow of ethylene and hydrogen gases to grow single wall carbon nanotubes by chemical vapor deposition. Strong coupling to the gate is inferred from transport measurements for both metallic and semiconducting tubes. At low-temperatures, our samples act as single-electron transistors where the transport mechanism is mainly governed by Coulomb blockade. The measurements reveal very rich quantized energy level spectra spanning from valence to conduction band. The Coulomb diamonds have similar addition energies on both sides of the semiconducting gap. Signatures of subbands po…

Temperature and Gas-Environment Dependent Electron and Phonon Transport in Suspended Carbon Nanotubes Up to Electrical Breakdown

High bias electrical transport characteristics of freely suspended metallic single-walled carbon nanotubes (SWNTs) are investigated at 250-400K in vacuum and various gases. Self-heating is exploited to examine the temperature dependence of phonon transport and optical phonon decay in SWNTs. The acoustic phonon thermal conductivity of a SWNT follows ~1/T at high temperatures. Non-equilibrium optical phonon effects in suspended nanotubes decrease as the ambient temperature increases. Gas molecules assist the relaxation of hot optical phonons along the tube length and enable enhanced current flow…

Phase transitions on the surface of a carbon nanotube

A suspended carbon nanotube can act as a nanoscale resonator with remarkable electromechanical properties and the ability to detect adsorption on its surface at the level of single atoms. Understanding adsorption on nanotubes and other graphitic materials is key to many sensing and storage applications. Here we show that nanotube resonators offer a powerful new means of investigating fundamental aspects of adsorption on carbon, including the collective behaviour of adsorbed matter and its coupling to the substrate electrons. By monitoring the vibrational resonance frequency in the presence of …

Effects of Microwave Absorption on Long and Short Single-Walled Carbon Nanotubes at 10-6 Torr

Carbon nanotubes have been observed to emit ultraviolet, visible and infrared radiation when exposed to microwaves. We have performed experiments in which both short (0.5 microns to 2 microns) and long (5 microns to 30 microns) single and double walled carbon nanotubes were exposed to 2.46 GHz microwaves at a pressure of 10^-6 Torr. Structural modifications of the-carbon nanotubes due to microwave absorption have been studied using the Raman spectroscopy G-band and D-band intensities, which suggest that microwave irradiation at relatively low pressure results in an increase in nanotube defects…