Multi-tube field-effect transistors (FETs) are assembled between two metallic electrodes using dielectrophoresis, in which a solution of dispersed single-walled carbon nanotubes (SWCNTs) is put between the electrodes, and an AC voltage with an amplitude of 5-8 V and a frequency of 300 kHz is applied [1,2]. After depositing the SWCNTs between the electrodes, the solution is blotted with a filter paper and the sample is dried with air. Room temperature I-V measurements are performed for such multi-tube devices which are found to have transistor-like behaviour in most cases. Further on, the devices are characterized with Atomic force microscopy (AFM) and electrostatic force microscopy (EFM). By applying a voltage to the AFM tip in lift mode [3], we are able to detect changes of the potential along the deposited SWCNT interconnects, and thus, to identify local defects in the transistor channels.

[1] S. Taeger, M. Mertig, Int. J. Mat. Res. 98, 742 (2007).
[2] N. Ranjan, M. Mertig, phys. stat. sol. (b) 245, 2311 (2008).
[3] T. P. Gotszalk, P. Grabiec, I. W. Rangelow, Materials Science 21, 333 (2003).