Single-walled carbon nanotube-based field-effect transistors (non-reviewed)

Abstract

Summary form only given. Single-walled carbon nanotubes (SWCNTs) have been considered as a promising nanostructured material for the realization of future nanoelectronic devices because of their unique electrical properties such as the ballistic transportation of electrons or holes in SWCNTs. In this paper, we report the fabrication of single-walled carbon nanotube field- effect transistors (CNTFETs) with metal and semiconductor materials as the source and drain materials. Ultra-purified HiPCO-grown single-walled carbon nanotubes (SWCNTs) from Carbon Nanotechnologies, Inc. (CNI) were used for the fabrication of CNTFETs. N-methyl pyrrolidone (NMP), dimethyl formamide (DMF), toluene and trifluoroacetic acid were used to disperse SWCNTs in solutions. The dispersion of SWCNTs in the solvents were ultrasonically assisted, and then centrifuged at 14000 rpm. The solubility of SWCNTs in the solvents was finally compared, and the degree of dispersion was examined by SEM. Dielectrophoresis (DEP) method was used to deposit, align, and assemble carbon nanotubes (CNTs) across the source and drain of CNTFETs to form the channel. Microfabrication techniques such as UV lithography and e-beam lithography were used to fabricate the CNTFETs. The gap between the source and drain varied from 800 nm to 3 um. Both metals such as gold and semiconductors such as bismuth telluride (Bi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Te <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) were used as the source and drain materials for the CNTFETs. The fabricated CNTFET has a backside gate with the substrate as the gate contact. Silicon dioxide was used as the gate oxide. Electron-beam evaporation and sputtering deposition were used for the deposition of the thin film layers in this research.The drain-source current (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</sub> ) versus drain-source voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</sub> ) and gate voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</sub> ) was characterized for the fabricated CNTFETs. It was found that the I-V behavior of metal electrode-based CNTFETs is dependent on the type (metallic or semiconducting) of aligned carbon nanotubes across the electrodes and the I-V behavior of semiconductor electrode-based CNTFETs is independent of the type of carbon nanotubes. This property makes the semiconductor electrode-based CNTFETs more promising than the metal electrode-based CNTFETs. The developed carbon nanotube field-effect transistors (CNTFETs) can be a good candidate for the application of nanoelectronics and integrated circuits with a high mobility and fast switching.