An Alternative Method for Determining Carbon Nanotube Band Energy

Abstract

Information technology is resulting from incredibly fast advances in electronics and computing during the last decades. Today, the electronics industry is producing metal-oxide-semiconductor field-effect transistors (MOSFETs) with critical dimensions of about 100 nm, and projections anticipate devices with minimum future sizes of around 50 nm in the year 2009 [1–10]. However, some critical technological barriers and fundamental limitations to size reduction are threatening the use of orthogonalized-plane-wave (OPW) method for calculation of band energy. The main difficulty with current crystalline potentials resides quite simply in considering electrons of carbon atoms as independent particles. One approach to overcoming these impending barriers involves finding on evaluating the potential of carbon nanotubes (CNTs) as the basis of a future nanoelectronics technology. Single-walled CNT (SWCNTs) are materials with unique properties. They have several millimeters in length and are strongly bonded covalent materials. Because of their extremely small diameter, the OPW method should be modified and completed with tight binding (TB) method due to the overlapping of wave function of electrons. The procedure is to augment the basis set of present method by including wave functions which are OPWs between nuclei of carbon atoms but represent modified Bloch waves near the nuclei. It means that by scaling the CNT dimension, the carbon atoms come close to each other and change the band energy. Thus, by using Ritz variational method [11], we have modified the band energy.