Laser-induced growth of diameter-modulated single-walled carbon nanotubes

Abstract

Periodic diameter modulation of individual carbon nanotubes (CNTs) by rapid temperature variation in laser-assisted chemical vapor deposition (LCVD) process was successfully achieved. A CO2 laser was used to quickly and precisely modulate the growth temperature. Due to inverse relationship between the diameter of SWNTs and the growth temperature, tapered and diameter-alternating tubes were grown by modulating the CO2 laser power during the growth. The diameter-modulated SWNTs were grown across a pair of Mo electrodes to form field-effect transistors (FETs) for investigation of their electrical and optical properties. Variations in the bandgap of the individual semiconducting SWNTs were detected meaning the formation of multi bandgaps within a single tube. Transmission electron microscopy and Raman spectroscopy were also studied to investigate the structural and electronic properties of the structures.Periodic diameter modulation of individual carbon nanotubes (CNTs) by rapid temperature variation in laser-assisted chemical vapor deposition (LCVD) process was successfully achieved. A CO2 laser was used to quickly and precisely modulate the growth temperature. Due to inverse relationship between the diameter of SWNTs and the growth temperature, tapered and diameter-alternating tubes were grown by modulating the CO2 laser power during the growth. The diameter-modulated SWNTs were grown across a pair of Mo electrodes to form field-effect transistors (FETs) for investigation of their electrical and optical properties. Variations in the bandgap of the individual semiconducting SWNTs were detected meaning the formation of multi bandgaps within a single tube. Transmission electron microscopy and Raman spectroscopy were also studied to investigate the structural and electronic properties of the structures.