Altering the Schottky Barrier Height and Conductance by Using Metal Nanoparticles in Carbon Nanotubes-Based Devices

Abstract

In this paper, we propose a novel technique to overcome the conductance limitation in metal contacted single-walled carbon nanotubes (SWNTs)-based devices using metal nanoparticles (MNPs). Schottky barrier (SB) height at metal-SWNTs contact is believed to be the major contributor for this conductance limitation. Metal contacts with SWNTs are fabricated on a thermally grown SiO2/Si substrate using a conventional lithography process. The SWNTs are aligned between the metal electrodes using dielectrophoresis method. MNPs are introduced in the device using a small drop of MNP suspension to decorate the SWNTs. It is observed that the introduction of MNPs in the device reduces the SB height significantly. We found 0.34 eV reduction in SB height with silver (Ag) nanoparticles (NPs) and 0.15 eV with gold (Au) NPs. The proposed technique has improved the conductance in decorated SWNTs four times for Ag and Au NPs as compared to the bare SWNTs. Improvement in the conductance behavior of the SWNTs using MNPs enhances the sensitivity and switching speed of the devices, therefore, make it a promising alternative to silicon-based devices.