Logic Ciucuits Using Solution-processed Single-walled Carbon Nanotue Transistors

This letter reports on the realization of logic circuits employing solution-processed networks of single-walled carbon nanotubes. We constructed basic logic gates (inverter, NAND and NOR) with n- and p-type field-effect transistors fabricated by solution-based chemical doping. Complementary metal-oxide-semiconductor inverters exhibited voltage gains of up to 20, which illustrates the great potential of carbon nanotube networks for printable flexible electronics.Comment: 12 PAGES, 3 FIGURE

Orbital and spin magnetic moments of transforming 1D iron inside metallic and semiconducting carbon nanotubes

The orbital and spin magnetic properties of iron inside transforming metallic and semiconducting 1D carbon nanotube hybrids are studied by means of local x-ray magnetic circular dichroism (XMCD) and bulk superconducting quantum interference device (SQUID) measurements. Nanotube hybrids are initially ferrocene filled single-walled carbon nanotubes (SWCNT) of different metallicities. After a high temperature nanochemical reaction ferrocene molecules react with each other to form iron nano clusters. We show that the ferrocenes molecular orbitals interact differently with the SWCNT of different metallicities without significant XMCD response. This XMCD at various temperatures and magnetic fields reveals that the orbital and/or spin magnetic moments of the encapsulated iron are altered drastically as the transformation to 1D Fe nanoclusters takes place. The orbital and spin magnetic moments are both found to be larger in filled semiconducting nanotubes than in the metallic sample. This could mean that the magnetic polarizations of the encapsulated material is dependent on the metallicity of the tubes. From a comparison between the iron 3d magnetic moments and the bulk magnetism measured by SQUID, we conclude that the delocalized magnetisms dictate the magnetic properties of these 1D hybrid nanostructures

Empirical formulation of broadband complex refractive index spectra of single-chirality carbon nanotube assembly

Assemblies of single-walled carbon nanotubes with a specific chiral structure are promising future optofunctional materials because of their strong light-matter coupling arising from sharp optical resonances of quasi-one-dimensional excitons. Their strong optical resonances, which lie in the infrared-to-visible wavelength region, can be selected by their chiralities, and this selectivity promises a wide range of applications including photonic and thermo-optic devices. However, the broadband complex optical spectra of single-chirality carbon nanotube assemblies are scarce in the literature, which has prevented researchers and engineers from designing devices using them. Here, we experimentally determine broadband complex refractive index spectra of single-chirality carbon nanotube assemblies. Free-standing carbon nanotube membranes and those placed on sapphire substrates were fabricated via filtration of the nanotube solution prepared by the separation method using gel chromatography. Transmission and reflection spectra were measured in the mid-infrared to visible wavelength region, and the complex refractive indices of nanotube assemblies were determined as a function of photon energy. The real and imaginary parts of the refractive indices of the nanotube membrane with a bulk density of 1 g cm(-3) at the first subband exciton resonance were determined to be approximately 2.7-3.6 and 1.3i-2.4i, respectively. We propose an empirical formula that phenomenologically describes the complex refractive index spectra of various single-chirality nanotube membranes, which can facilitate the design of photonic devices using carbon nanotubes as the material

Temperature dependence of time-resolved luminescence spectra for 1D excitons in single-walled carbon nanotubes in micelles

Abstract We have investigated exciton luminescence spectra, decay behaviors, and their temperature dependence in singlewalled carbon nanotubes in micelles. The temperature dependence of luminescence spectra can be explained by the onephonon process associated with the radial breathing mode in the single-walled carbon nanotube. The luminescence decay behavior suggests that the signal is composed of various exponential decays with different decay times. These experimental results are explained by the existence of trapping centers on the nanotube.