Direct nano-wiring carbon nanotube using growth barrier: A possible mechanism of selective lateral growth

Abstract

In this work we report the direct nano-bridging of carbon nanotubes (CNT) between micro-sized islands using conventional photolithography technique necessary for the nanomachining and the molecular device applications compatible with the Si-based process. The most distinct feature in this work is to use a growth barrier of Nb metal or insulating layer on the top of the catalytic metal to prevent the growth of CNT from the vertical direction to the substrate. As a result, CNTs of either “straight line” or a perfect “Y shape” were selectively grown between lateral sides of the catalytic metals or pre-defined electrodes without any trace of vertical growth. The length of the CNTs was 500–1000 nm and the diameter thinner than about 20 nm. We suggest that magnetic and crystallographic characteristics due to the unique interaction between the Nb overlayer and ferromagnetic Ni catalysts and nano-granulation of Ni layer during the growth process are important for the lateral (i.e., parallel to the substrate) CNTs growth. These results clearly indicate that this method would be one of the most feasible fabrication techniques for the nanomachines or the electronic applications with a high integration level.

Wafer-level assembly of carbon nanotube networks using dielectrophoresis

“…Carbon nanotubes (CNTs) have the potential to become building blocks for practical nanoscale electronic devices. Their thermal, mechanical, chemical stability, and large current-carrying capacity make them attractive for applications in electrical interconnects [1,2], field-effect transistors [1,3], cold cathode field emitters [4,5], and sensors [6,7]. One of the primary hurdles in developing such novel CNT devices is reliable fabrication in a batch process.…”

High-Density, Large-Area Single-Walled Carbon Nanotube Networks on Nanoscale Patterned Substrates

“…The unique electronic and mechanical properties of carbon nanotubes offer enormous potential for various applications. − The most promising applications of nanotubes are those involving use in nanoelectronics such as a field effect transistor, − nanotube interconnects, − and nanosensors by virtue of their specific electronic structures and transport properties (high current density up to 10 9 A/cm 2 and ballistic conductance) , with their smaller dimensions. However, for building integrated self-assembled nanotube-based systems, it is required to controllably produce high-density single-walled carbon nanotube (SWNT) networks on a large scale.…”

Straightening Suspended Single Walled Carbon Nanotubes by Ion Irradiation

“…Normally growth produces nanotubes that are not straight between pillars and and that sag because the lengths of nanotubes grown are not equivalent to the separation between pillars. This produces a high percentage of the nanotube lengths in networks having improper orientation with respect to the overall alignment of the nanotubes in the network and could be a detriment in applications such as electrical wires/interconnects. − This could lead to shorting between wires, particularly if there are also nanotubes on the substrate that do not conform to the suspended network of nanotubes above. Similar is the case if the nanotube network needs to be used as a versatile template for attaching molecules and using them for applications such as sensors …”