Metal-Free Carbon Nanotube Growth for Nanoelectronics Applications

The investigators at the University of Southampton have been combining expertise in SiGeC epitaxy in the School of Electronics & Computer Science with expertise in carbon nanotube growth in the School of Physics & Astronomy in a series of proof of principle experiments. These experiments have clearly demonstrated an entirely new method of producing carbon nanotubes using carbon implanted germanium quantum dots on silicon, which enables single and multi- walled carbon nanotubes to be grown without the need for metal catalysts. The absence of metal in the growth process is an important advantage for this new method because it will allow carbon nanotubes to be integrated on the same wafer as silicon nanoelectronics without introducing undesirable metallic contamination. This proposal brings together expertise in the materials science of carbon nanotubes at the University of Oxford with expertise in silicon processing and carbon nanotube growth at the University of Southampton. We seek to put our understanding of these exciting new results on a solid scientific foundation and at the same time to improve the yield, density and distribution of the nanotubes. The growth conditions will be systematically varied and a variety of characterisation techniques (Raman, SEM, TEM etc.) applied to characterise the nanotubes and identify the nature of the seeds. Carbon ion implantation and SiGe:C epitaxy will be compared as approaches for seeding the nanotube growth. If this latter approach is found to be effective, a growth process will be developed that allows the seed layers and the carbon nanotubes to be grown in a single step, thereby providing an attractive route to exploitation for our patented growth process. Finally, proof of principle electrical characterisation of the carbon nanotubes will be performed.