CARBON NANOTUBE GROWTH ON ELECTROCHEMICALLY ENGINEERED S URFACE

Abstract

Carbon nanotubes are most studied material in the field of nano materials due to its numerous possible applications. These applications need different parameters to be taken care for better control and enhancement of desired properties. Several methods like arc discharge. laser - ablation, electrolysis and chemical vapour deposition (CVD) have been tried to grow carbon nanotubes to attain better quality carbon nanotubes as well as higher yield. CVD is being considered to be the method fulfilling the requirement of high yield and good quality. With the increasing interest in carbon nanotubes, alignment becomes important for some applications. Researchers are using lithography and/or support layer and lithography for growing vertically aligned carbon nanotubes. Support layer acts as surface modifier to stabilize catalyst site, but it offers extra resistance that is not desirable for field emission. Hence, a simpler process need to be developed which can control catalyst deposition sites and also offer some degree of alignment without application of any intermediate layer. In the present research, copper is taken as substrate material as it has good thermal and electrical conductivity .Carbon nanotubes are grown by chemical vapour deposition method on pitted samples to achieve limited area growth and possible alignment. Here no interface or support layer is used during CNT growth; so that resistance is minimized. Pits are produced by potentiostatic corrosion test. After potentiostatic corrosion, substrate is cleaned by ultrasonication for 10 minutes, followed by catalyst deposition by electrochemical method and removal of extra catalyst, those are out of pits, by cloth polishing using magnesium oxide as abrasive material. CNTs are characterized by SEM, XRD, TEM and Raman spectroscopy and their field emission behaviour is studied.