1. A semiconductor device structure comprising: a gate electrode including a vertical sidewall and a gate dielectric covering the vertical sidewall; at least one semiconducting carbon nanotube extending vertically between opposite first and second ends at a location adjacent to said vertical sidewall of said gate electrode; a first contact electrically coupled with said first end of said at least one semiconducting carbon nanotube; and a second contact electrically coupled with said second end of said at least one semiconducting carbon nanotube.