Nano-scale gap Single-Walled Carbon Nanotubes (SWNTs) device has emerged as an excellent candidate for nanoelectronic and sensor application. The small diameter of carbon nanotubes almost matches to the chemical and biological size of the interacting species causing more contact of surface areas which allows better signal transfer in the device. Carbon nanotubes’ one dimensional structure and its high current mobility also make it the suitable candidate for nano-scale electrical interconnect material.
In this study, we had successfully controlled the gap distance of SWNTs devices and fabricated devices with three different gap distances. Nano-scale gap SWNTs devices are fabricated by combining ultrasonication, filtration and electrochemical deposition method. The overall experimental procedure is divided into three steps. For the first step, we carried out the process of preparing SWNTs solution which involves the surface modification and the technique of positioning SWNTs into AAO channels. We had successfully centralized the SWNTs in AAO channels. This condition is important for mass production of the nano-scale gap device containing SWNTs, stable SWNTs electrical contact as well as excellent charge carrier flow properties. In the second step, multi-segmented nanorods (Au-Ni-Au) are grown inside the AAO channels. The SWNTs gap distances are controlled and created by disolving the Ni from the nanorod. Thus, SWNTs devices with precisely controlled gap distances are obtained. The controlled gap distances are of 34 ± 6 nm, 66 ± 3 nm and 107 ± 22 nm, respectively. The presences of SWNTs attached to both Au nanorods are confirmed by Micro-Raman spectroscopy. The Raman spectra shows G-band peak at 1592 cm-1, which indicates the semiconducting property of carbon nanotubes. The I-V measurement performed using semiconductor parameter analyzer, shows that small gap distance possess higher charge mobility compared to longer gap distance. The I-V curve also reveals the semiconducting property with Schottky barrier effect while the three terminal SWNTs device shows the FET property. From this study we demonstrate an easy and effective method to fabricate nano-scale gap controlled SWNT devices with optimized fabrication condition.