On Contact Resistance of Carbon Nanotubes

Carbon nanotubes (CNTs) have found many potential applications stemming from their small dimensions and marvellous electronic, mechanical, and thermal properties. One of the barriers for using CNTs as building blocks in nanoelectronics is the high contact resistance. This paper reviews recent progress on the research of contact resistance of CNTs. It starts with a preview of two basic contact configurations, i.e., side contact and end contact, and measurements of contact resistance. The formation of Schottky barrier on a typical metal-semiconductor contact is then presented, aiming at looking for ways to reduce contact resistance from a theoretical point of view. The current techniques for improving CNT contact resistance are classified and summarized as well. The principles and applicabilities of these techniques are compared and discussed. A deep understanding of the forming mechanisms and improvement methods of contact resistance is critical in order to bring CNT-based devices from laboratory to the real-world technology.