新技术可增加纳米碳管的密度

Carbon nanotubes' outstanding mechanical, electrical and thermal¹ properties make them an alluring²（诱惑的） material to electronics manufacturers. However, until recently scientists believed that growing the high density³ of tiny graphene cylinders⁴ needed for many microelectronics applications would be difficult. Now a team from Cambridge University in England has devised a simple technique to increase the density of nanotube forests grown on conductive supports about five times over previous methods. The high density nanotubes might one day replace some metal electronic components⁵, leading to faster devices. The researchers report their finding in the journal Applied⁶ Physics Letters, which is produced by AIP Publishing.   "The high density aspect is often overlooked in many carbon nanotube growth processes, and is an unusual feature of our approach," says John Robertson, a professor in the electronic devices and materials group in the department of engineering at Cambridge. High-density forests are necessary for certain applications of carbon nanotubes, like electronic interconnects and thermal interface⁷ materials, he says.   Robertson and his colleagues grew carbon nanotubes on a conductive copper⁸ surface that was coated with co-catalysts cobalt（钴） and molybdenum（钼）. In a novel approach, the researchers grew at lower temperature than is typical which is applicable in the semiconductor⁹ industry. When the interaction of metals was analyzed¹⁰ by X-ray photoelectron spectroscopy, it revealed the creation of a more supportive substrate for the forests to root in. The subsequent nanotube growth exhibited the highest mass density reported so far.   "In microelectronics, this approach to growing high-density carbon nanotube forests on conductors can potentially replace and outperform the current copper-based interconnects in a future generation of devices," says Cambridge researcher Hisashi Sugime. In the future, more robust¹¹ carbon nanotube forests may also help improve thermal interface materials, battery electrodes, and supercapacitors.