Researchers from the Department of Electronic and Computer Engineering at Hong Kong University of Science and Technology (HKUST) have developed a technique to grow high-density horizontal carbon nanotubes on silicon. As shown in the image, the carbon nanotubes are well aligned in the horizontal direction. The scientists have demonstrated the growth of carbon nanotubes ranging from 12 to 103 tubes per micrometre by controlling the catalyst thickness. This growth technique has major ramifications on the use of carbon nanotubes for nanoelectronics, including next-generation integrated circuit interconnects and field effect transistors.

The HKUST team used the plasma-induced electric-field to guide the direction of the carbon nanotube growth. The plasma charging during PECVD growth created a plasma-induced electric-field at the interface between the substrate surface and plasma. The induced field is typically vertical relative to the substrate surface. To create a horizontal electric-field, the HKUST researchers designed micro-structures with insulating sidewalls.

More details can be found in the journal Nanotechnology.