Two-terminal nanotube devices including a nanotube bridge and methods of making same

A nanotube switching device, comprising:

• a conductive terminal extending up from a substrate, the conductive terminal defining a first boundary of a void and a vertical wall of substrate material defining a second boundary of a void;
• an interconnect line disposed in the void, providing an electrical communication pathway to and from external circuitry;
• a nanotube article having an unaligned network of nanotubes, said article being arranged to permanently contact at least a portion of each of the conductive terminal and the interconnect line, and suspended over the void;
• and
• a stimulus circuit in electrical communication with conductive terminals,
• said stimulus circuit generating and applying waveforms to the conductive terminal to induce a change in the resistance of the nanotube article between a relatively low resistance and a relatively high resistance,
• wherein the relatively high resistance corresponds to a first state of the device, and wherein the relatively low resistance corresponds to a second state of the device.

A method of fabricating a nanotube switching device, comprising:

• embedding at least one electrode in a substrate;
• forming a patterned region of nanotube fabric, the patterned region of nanotube fabric being arranged to permanently contact at least a portion of the electrode;
• removing a selected portion of the substrate, adjacent to the at least one electrode, to define a void in the substrate bounded in part by the electrode, such that the patterned region of nanotube fabric forms another boundary of the void in the substrate;
• and
• providing a stimulus circuit in electrical communication with the at least one electrode,
• said stimulus circuit generating and applying one or more waveforms to the at least one electrode to induce a change in the resistance of the patterned region of nanotube fabric between a relatively low resistance and a relatively high resistance,
• wherein the relatively high resistance corresponds to a first state of the device, and wherein the relatively low resistance corresponds to a second state of the device.