Characteristics of aggregated single-walled carbon nanotube (SMINT) as a channel of field effect transistors (FETs) were examined. SWNTs were dispersed in a solution of dimethylformamide in a narrow bundle structure to form non-aligned arrays, which became channels of FETs. The network-SWNT-FETs produced in this solution process was found to have a mobility of 10.9 cm(2)/V s, approximate to100 times as high as those reported for other solution-processed organic thin-film FETs formed by solution processes, and the present product exhibited the ambipolar character observed in individual-SWNT-FETs. (C) 2004 Elsevier B.V. All rights reserved.