A simple method for generating nano-pillars and uniformly separated nano-needle arrays on silicon

A simple method is presented to generate pillared and uniformly spaced nano-needle arrays formed by electrochemical modification of nano-walled, densely packed, pore structures with pore diameters that have minimum variation. Needle structures generated in a single etch procedure are between three and four micrometers tall and taper to points 10 nm or less in diameter. The tip-to-tip spacing is found to be the same as the precursor pore diameter and is nearly uniform at 1 μm. These structures may be useful for intracellular recording. The results obtained appear to be competitive with laser ablation in that a needle array structure of a more uniform height and separation can be formed with a much less complex and expensive procedure.