Researchers at the University of Nebraska-Lincoln (UNL) have incorporated these variations into individual SWNTs. A laser-assisted chemical vapour deposition (LCVD) method was used to alter the diameters of the SWNTs in different segments due to the inverse relationship between the diameter and growth temperature.

Diode-like behaviour

SWNTs with modulated diameters were grown across Mo electrodes to investigate their electronic transport characteristics. Diode-like behaviour of the structures provided clear evidence of bandgap difference at the two ends of the tubes, which is due to the inverse relationship between the diameter and the bandgap in s-SWNTs. This technique demonstrates an easy and convenient approach for fabricating SWNT-based hybrid structures.

The researchers presented their work in the journal Nanotechnology.