The authors demonstrate directed assembly of high quality solution processed single-walled carbon nanotube (SWNT) devices via ac dielectrophoresis using commercially available SWNT solutions. By controlling the shape of the electrodes, concentration of the solution, and assembly time, the authors are able to control the assembly of SWNTs from dense arrays down to individual SWNT devices. Electronic transport studies of individual SWNT devices show field effect mobilities of up to 1380 cm(2)/V s for semiconducting SWNTs and saturation currents of up to similar to 15 mu A for metallic SWNTs. The field effect mobilities are more than an order of magnitude improvement over previous solution processed individual SWNT devices and close to the theoretical limit. Field effect transistors (FET) fabricated from aligned two-dimensional arrays of SWNT show field effect mobility as high as 123 cm(2)/V s, which is three orders of magnitude higher than the solution processed organic FET devices. This study shows promise for commercially available SWNT solution for the parallel fabrication of high quality nanoelectronic devices. (c) 2010 American Vacuum Society. [DOI: 10.1116/1.3501347]