Spatially Resolved Transport Properties of Pristine and Doped Single-Walled Carbon Nanotube Networks

• Published in: Journal of physical chemistry. C Vol. 117; no. 25; pp. 13324 - 13330
• Main Authors: Znidarsic, Andrej, Kaskela, Antti, Laiho, Patrik, Gaberscek, Miran, Ohno, Yutaka, Nasibulin, Albert G, Kauppinen, Esko I, Hassanien, Abdou
• Format: Journal Article
• Language: English
• Published: Columbus, OH American Chemical Society 27.06.2013
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electron, ion, and scanning probe microscopy; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in multilayers, nanoscale materials and structures; Exact sciences and technology; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Materials science; Nanoscale materials and structures: fabrication and characterization; Nanotubes; Physics; Scanning probe microscopy: scanning tunneling, atomic force, scanning optical, magnetic force, etc; Structure of solids and liquids; crystallography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Atomic force microscopy; Singlewalled nanotube; Electrical conductivity; Transport properties; Sheet resistivity; Morphology; Doping; Contact resistance; Carbon; Spatial resolution; Nitric acid
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp403983y

We use noninvasive atomic force microscopy to probe the spatial electrical conductivity of isolated junctions of pristine and nitric acid treated single-walled carbon nanotube networks (SWCNT-N). By analyzing the local IV curves of SWCNTs and bundles with various diameters, the resistance per unit length and the contact resistance of their junctions are estimated to be 3–16 kΩ/μm and 29–532 kΩ, respectively. We find that the contact resistance decreases with increasing SWCNT or bundle diameter and depends on the contact morphology, reaching a value of 29 kΩ at a diameter of 10 nm. A nitric acid treatment moderately dopes SWCNTs and reduces their average contact resistance by a factor of 3 while the resistance of the nanotubes remains largely unaltered. Remarkably, the same treatment on an SWCNT-N shows similar reduction in the sheet resistance by a factor of 4. These results suggest that the resistance reduction mechanism is related to the contact modulation with no major impact on conductance of SWCNTs.