Nano semiconductor switch devices are provided that include a semiconductor substrate and a conductive layer on the semiconductor substrate. A first insulating layer is provided on the conductive layer and the semiconductor substrate. The first insulating layer defines a contact hole that exposes at least a portion of the conductive layer. Carbon nano tubes are provided on the exposed portion of the conductive layer in the contact hole. The carbon nano tubes are in a vertical direction with respect to the semiconductor substrate. Related methods of fabrication are also provided herein.