Abstract: A multi-layer H2 sensor includes a carbon nanotube layer, and a ultra-thin metal or metal alloy layer in contact with the nanotube layer. The ultra-thin metal or metal alloy layer is preferably from 10 to 50 angstroms thick. An electrical resistance of the layered sensor increases upon exposure to H2 and can provide detection of hydrogen gas (H2) down to at least 10 ppm, The metal or metal alloy layer is preferably selected from the group consisting of Ni, Pd and Pt, or mixtures thereof. Multi-layered sensors and can be conveniently operated at room temperature.

Abstract: A semiconductor device includes at least one semiconductor layer, a metal layer in electrical contact with the semiconductor layer, and a carbon nanotube contact layer interposed between the metal layer and the semiconductor layer. The contact layer electrically couples the metal layer to the semiconductor layer and provides a semiconductor contact having low specific contact resistance. The contact layer can be substantially optically transparent layer in at least a portion of the visible light range.