Patent ID: 7754182

Claim:
A method for forming a carbon nanotube array, comprising: providing a smooth substrate; depositing a catalyst layer on the substrate; placing the substrate in a furnace; heating the furnace to a first temperature, the first temperature being in a range from about 500° C. to about 700° C.; introducing a mixture of carbon source gas and a protective gas into the furnace; keeping a temperature of the catalyst layer at a second temperature while maintaining a partial pressure of the carbon source gas lower than 20% by actively adjusting a flow rate of the carbon source gas during growth of carbon nanotubes, whereby the second temperature is at least 50° C. higher than the first temperature and the difference between the first and second temperature is based solely upon a heat released by an exothermic reaction caused by the reaction between the carbon source gas and the catalyst; and growing a carbon nanotube array on the smooth substrate, the carbon nanotube array comprising of carbon nanotubes, wherein the carbon nanotubes' growth rate is increased as a result of the exothermic reaction, and the grown carbon nanotubes have clean smooth surfaces such that adjacent carbon nanotubes are bundled together by Van der Waals force therebetween.