A two terminal memory device includes first and second conductive terminals and a nanotube article. The article has at least one nanotube, and overlaps at least a portion of each of the first and second terminals. The device also includes stimulus circuitry in electrical communication with at least one of the first and second terminals. The circuit is capable of applying first and second electrical stimuli to at least one of the first and second terminal(s) to change the relative resistance of the device between the first and second terminals between a relatively high resistance and a relatively low resistance. The relatively high resistance between the first and second terminals corresponds to a first state of the device, and the relatively low resistance between the first and second terminals corresponds to a second state of the device.

A three-dimensional array especially adapted for memory elements that reversibly change a level of electrical conductance in response to a voltage difference being applied across them. Memory elements are formed across a plurality of planes positioned different distances above a semiconductor substrate. Bit lines to which the memory elements of all planes are connected are oriented vertically from the substrate and through the plurality of planes.