Bottom-down Nanomanufacturing

This research is to establish fundamental engineering principles for a new innovative nanomanufacturing process based on localized delivery and release of reactive etching chemicals. Our approach employs engineered nanoparticles that can be attached to a desired substrate surface and then release chemical etchants to selectively etch the substrate in regions under the adsorbed nanoparticles. Upon removal of the nanoparticles, the localized etching of the substrate is accomplished.

The entire process can be viewed as a “nanofabrication version of the targeted drug delivery”. This maskless localized etch approach is drastically different from the conventional etch processes used to fabricate structural features into the substrate. It has many advantages over the current etch processes – no need for cleanroom or expensive equipment, suitable for mass production; fully conformal nanofabrication onto three dimensional objects; easy control of fabricated feature size and shape, and inherently safe design. These attributes provide not only the cost effectiveness but also the sustainability of the process. This work is in collaboration with Prof. D. Velegol.

The poly(3,4-ethylenedioxythiophene) conducting polymer was grown via a vapor-phase polymerization on a nonwoven porous mat of polystyrene nanofibers containing ferric p-toluenesulfonate.  The fibers in the mat could be melt-welded by condensing the monomer vapor on the PS template fiber during the polymerization.
Localized etching of a silicon (100) wafer upon hydrolysis of amidine-functionalized polystyrene latex (APSL) colloids. The nanowell size can be precisely controlled with the size of the APSL colloids. No etch mask is needed and the region outside the nanowells is not etched at all. Scale Bar = 500 nm.