Free-standing Carbon Nanotube Films Research Articles

Nonenzymatic Glucose Sensor Using Freestanding Single-Wall Carbon Nanotube Films

Freestanding single-wall carbon nanotube (SWNT) films with large area were synthesized by the floating chemical vapor deposition technique. A glucose sensor was constructed using the SWNT films for direct oxidation of glucose in alkaline solution. The SWNT film electrode showed a high and reproducible sensitivity of 248.6 μA/cm 2 mM to glucose with a response time of less than 10 s in 0.1 M alkaline solution, even in the presence of 0.2 M chloride ions. These results demonstrate that the SWNT films have potential applications in constructing highly sensitive, stable, and fast response glucose sensors without enzyme loading. © 2007 The Electrochemical Society. [DOI: 10.1149/1.2710184] All rights reserved.

Charge dynamics in transparent single-walled carbon nanotube films from optical transmission measurements

We report the transmission over a wide frequency range (far infrared - visible) of pristine and hole-doped, free-standing carbon nanotube films at temperatures between 50 K and 300 K. Optical constants are estimated by Kramers-Kronig analysis of transmittance. We see evidence in the far infrared for a gap below 10 meV. Hole doping causes a shift of spectral weight from the first interband transition into the far infrared. Temperature dependence in both the doped and undoped samples is restricted to the far-infrared region.

Preparation of Silicon-on-Insulator Substrate on Large Free-Standing Carbon Nanotube Film Formation by Surface Decomposition of SiC Film

Epitaxial 3C–SiC films were grown on silicon-on-insulator (SOI) substrates with [111] and [100] orientations by a chemical vapor deposition (CVD) method using an alternating gas supply. The SiC films were removed from the SOI substrates by chemical etching treatments. The sizes of the free-standing SiC (111) films, which were restricted by crack formation during the etching process, depended on the thickness and crystal quality of the silicon overlayer (SOL) on SOI substrates, while that of the free-standing SiC (100) film was maintained even after the etching. Carbon nanotubes (CNTs) were formed on both C and Si faces of the SiC (111) films by surface decomposition at 1973 K at 1.33×10-2 Pa. The growth rate of CNTs on the C face was three times faster than that of CNTs on the Si face. A free-standing CNT film was formed after complete surface decomposition of the SiC film. The area of the free-standing CNT film was about 80 mm2. On the other hand, graphite was formed on the SiC (100) film surface which was removed from the SOI (100) substrate.