Doping-Free Nanoscale Complementary Carbon-Nanotube Field-Effect Transistors with DNA-Templated Molecular Lithography

Sub-30-nm complementary doping-free carbon nanotube-field effect transistor (carCNT-FET) devices were fabricated in a controlled environment using DNA-templated molecular lithography. The single walled NT (CWNT) were selectively assembled through attractive coulombic interaction with the pre-patterned hydrophobic self-assembled fluorocytltichlorosilane (FOTS) terminated by a fluoromethyl group. The estimated lengths of the dsDNA with the sequence used is found to be 13.6-nm with 40-mer and 20.4-nm with 60-mer. The relatively small breakdown voltage of the 13.6 nm nanogap originates from the concentrated electric field at the rough surface of the Au/Cr structure. The drain current saturated at a high drain bias implies that backscattered carriers exist due to optical or zone-boundary phonon emissions with a high drain bias.