Localized growth of suspended SWCNTs by means of an all-laser process and their direct integration into nanoelectronic devices

We have successfully developed an all-laser processing for the localized growth of suspended single-wall carbon nanotubes (SWCNTs) on prepatterned SiO2/Si substrates. Our all-laser process stands out by its exclusive use of the same KrF excimer laser, first, to, deposit the embedded-catalyst electrodes with a controllable architecture and, second, to grow SWCNTs through the pulsed laser ablation of a pure graphite target. Under the optimal growth conditions, the suspended SWCNTs are shown to bridge laterally adjacent electrodes separated by a gap of similar to 2 mu m. These SWCNTs (having diameters in the 1.25-1.64-nm range) generally tend to auto-assemble into bundles of similar to 5-15 nm in diameter. The all-laser process here developed offers the advantage of a direct integration of the SWCNTs into field-effect-transistor-like devices with no postprocessing, thereby permitting the investigation of their electrical transport properties. Thus, the suspended SWCNT bundles are shown to behave collectively as an ambipolar transistor with ON/OFF switching ratios as high as similar to 10(4).