The inherent alignment in carbon nanotube "carpet" structures makes possible a variety of applications particularly for electronic device implementation. A method has been developed for transferring a carpet to a conductive substrate, to enable implementation for electronic devices. Methods for manipulating the size of the nanoparticle growth catalyst through controlled acid etch and for creating highly dense structures of aligned nanotubes from carpets by liquid processing are presented. One of the most promising, near-term applications for nanotube carpets is as the basis for a solid-state, ultra-high energy/ultra-high power "supercapacitor." Modeling of capacitance characteristics, fabrication methods and electrical characterization data are presented.