End-bonding multiwalled carbon nanotubes in alumina templates: Superconducting proximity effect

Abstract

We cut off the top parts of multiwalled carbon nanotubes (MWNTs), which are synthesized in the nanopores of an alumina template and grown over the template surface from the pores, by utilizing ultrasonic cleaning. This leads to highly regularly aligned MWNTs with open top ends and tubes of the same length in the template. These open top ends can be end-bonded by evaporating gold/niobium electrodes and performing optimal annealing. We find that these niobium/MWNTs junctions result in highly transparent interfaces. As evidence, proximity-induced superconductivity and supercurrents are shown in the MWNTs.