Deposition and Alignment of Carbon Nanotubes with Dielectrophoresis for Fabrication of Carbon Nanotube Field-Effect Transistors

Semiconducting carbon nanotubes (CNTs) were dispersed ultrasonically in the Nmethyl-2-pyrrolidone (NMP) solvent, and were aligned and patterned with the alternating electric field-directed dielectrophoresis (DEP) method. CNT transistors were fabricated with the DEP-patterned semiconducting CNTs. Clean room-based micro- and nanofabrication techniques such as UV lithography and lift-off process were used to fabricate the CNT devices. The patterned semiconducting carbon nanotubes and fabricated transistors were imaged using the scanning electron microscope (SEM), and the current-voltage (IV) curves were obtained. It was found that the gap between the opposite electrodes affected the patterning of CNTs in the DEP process; the CNT transistors had excellent current-voltage (IV) curves of p-channel filed-effect transistors with high ratios of on/off source-drain current values, and the semiconducting CNTs could achieve a higher yield in the device fabrication.