High aspect ratio silicon dioxide-coated single-walled carbon nanotube scanning probe nanoelectrodes
We have fabricated high aspect ratio, hydrophilic nanoelectrodes from individual single-walled carbon nanotubes (SWNTs) mounted on conductive atomic force microscope (AFM) tips for use as electrochemical probes. Individual SWNTs with an average diameter of 5 nm and up to 1.5 μm in length were passivated with nanometer-thick SiO_2 films, deposited conformally in an inductively coupled plasma reactor. The electrically insulating SiO_2 films improved the nanotube rigidity and stabilized the nanotube−AFM tip contact to enable use in aqueous environments. The nanotube tip was successfully exposed by subjecting the probe to nanosecond electrical pulse etching but only after electron beam irradiation in a transmission electron microscope (TEM). Probe functionality was verified by electrodepositing gold nanoparticles from aqueous solution only at the exposed tip.
Additional Information© 2009 American Chemical Society. Received: February 5, 2009; Revised Manuscript Received: February 20, 2009. The authors thank Carol Garland for assistance with TEM imaging. Nicholas Brunelli provided invaluable expertise with the ICP reactor. This work was supported by Arrowhead Research and Intel Corporation.
Supplemental Material - Narui2009p2403J_Phys_Chem_C_supp.pdf