Effect of Metal Oxide Nanoparticles on Carbon Nanotube Device Characteristics

In this paper, we investigate the reduction of the Schottky barrier (SB) height at the metal and semiconducting single-walled carbon nanotube (SWNT) junction by the decoration of SWNTs using metal oxide nanoparticles (NPs). Interdigitated electrodes are fabricated (finger length 40 mu m, width 3 mu m, with space of 3 mu m) on thermally grown silicon dioxide substrate. Thereafter, the SWNTs are aligned between the interdigitated electrodes. Following the decoration of SWNTs using metal oxide NPs, the devices are characterized. Decoration of SWNTs with metal oxide NPs reduces the SB height significantly. We find a reduction of SB height by 91 meV with titanium dioxide (TiO2) NPs and 150 meV with zinc oxide (ZnO) NPs. As compared to the bare SWNTs, the conductance of the devices improves by similar to 1.5X and similar to 2.1X due to the decoration of the SWNTs using TiO2 and ZnO NPs, respectively. This technique is of vital importance in decreasing the response time and enhancing the switching speed of the CNT-based sensors.