Patent ID: 7947542

Claim:
A method for making a thin film transistor, the method comprising the steps of: (a) providing a carbon nanotube array and an insulating substrate; (b) pulling out a first carbon nanotube film and a second carbon nanotube film from the carbon nanotube array by using a tool, each of the first and second carbon nanotube films comprising a plurality of carbon nanotubes being primarily oriented along the same direction; (c) forming a semiconducting layer by: placing the first carbon nanotube film on a surface of the insulating substrate along a first direction; and stacking the second carbon nanotube film on the first carbon nanotube film along a second direction such that the carbon nanotubes in the first carbon nanotube film are oriented along a different direction than the carbon nanotubes in the second carbon nanotube film; (d) forming a source electrode, a drain electrode, and a gate electrode; and (e) covering the carbon nanotube layer with an insulating layer; wherein the source electrode and the drain electrode are spaced from each other, and electrically connected to the carbon nanotube layer; the gate electrode is located on the insulating layer and electrically insulated from the carbon nanotube layer by the insulating layer.