On-Chip Band Gap Engineering of Carbon Nanotubes

Abstract

In this chapter, an electrical breakdown system for multiwalled CNTs (MWCNTs) is discussed to control the band gap of the MWCNT. The system plays an important role in the nanomanufacturing of CNT-based devices, and can be used as a reliable post treatment after the CNTs are deposited on the metal electrodes. The development of the system includes research into a real-time CNT electrical breakdown controller and an extended Kalman filter (EKF) for fault detection, which determines the breakdown status. By controlling the diameter of a MWCNT, a specific band gap material can be generated. The MWCNT consists of multilayer of carbon shells and can be either semiconducting or metallic. Theoretical and experimental studies have shown that the outermost layer of the MWCNT dominates the electrical conductivity of the MWCNT. To precisely adjust the band gap, one starts with a MWCNT with a relatively large diameter and small band gap. The electrical breakdown process is then used to remove the outermost layer of the MWCNT. © 2012 Elsevier Inc. All rights reserved.