Abstract: Manufacturers encounter limitations in forming low resistance ohmic electrical contact to semiconductor material P-type Gallium Nitride (p-GaN), commonly used in photonic applications, such that the contact is highly transparent to the light emission of the device. Carbon nanotubes (CNTs) can address this problem due to their combined metallic and semiconducting characteristics in conjunction with the fact that a fabric of CNTs has high optical transparency. The physical structure of the contact scheme is broken down into three components, a) the GaN, b) an interface material and c) the metallic conductor. The role of the interface material is to make suitable contact to both the GaN and the metal so that the GaN, in turn, will make good electrical contact to the metallic conductor that interfaces the device to external circuitry. A method of fabricating contact to GaN using CNTs and metal while maintaining protection of the GaN surface is provided.

Abstract: A method for arranging nanotube elements within nanotube fabric layers and films is disclosed. A directional force is applied over a nanotube fabric layer to render the fabric layer into an ordered network of nanotube elements. That is, a network of nanotube elements drawn together along their sidewalls and substantially oriented in a uniform direction. In some embodiments this directional force is applied by rolling a cylindrical element over the fabric layer. In other embodiments this directional force is applied by passing a rubbing material over the surface of a nanotube fabric layer. In other embodiments this directional force is applied by running a polishing material over the nanotube fabric layer for a predetermined time. Exemplary rolling, rubbing, and polishing apparatuses are also disclosed.

Abstract: 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.

Abstract: Under one aspect, a nonvolatile nanotube diode includes: a substrate; a semiconductor element disposed over the substrate, the semiconductor element having an anode and a cathode and capable of forming an electrically conductive pathway between the anode and the cathode; a nanotube switching element disposed over the semiconductor element, the nanotube switching element including a conductive contact and a nanotube fabric element capable of a plurality of resistance states; and a conductive terminal disposed in spaced relation to the conductive contact, wherein the nanotube fabric element is interposed between and in electrical communication with the conductive contact and the conductive contact is in electrical communication with the cathode, and wherein in response to electrical stimuli applied to the anode and the conductive terminal, the nonvolatile nanotube diode is capable of forming an electrically conductive pathway between the anode and the conductive terminal.

Abstract: Under one aspect, a method of cooling a circuit element includes providing a thermal reservoir having a temperature lower than an operating temperature of the circuit element; and providing a nanotube article in thermal contact with the circuit element and with the reservoir, the nanotube article including a non-woven fabric of nanotubes in contact with other nanotubes to define a plurality of thermal pathways along the article, the nanotube article having a nanotube density and a shape selected such that the nanotube article is capable of transferring heat from the circuit element to the thermal reservoir.

Abstract: A non-volatile latch circuit is provided. The non-volatile latch circuit includes a nanotube switching element capable of switching between resistance states and non-volatilely retaining the resistance state. The non-volatile latch circuit includes a volatile latch circuit is capable of receiving and volatilely storing a logic state. When the nanotube switching element is a resistance state, the volatile latch circuit retains a corresponding logic state and outputs that corresponding logic state at an output terminal. A non-volatile register file configuration circuit for use with a plurality of non-volatile register files is also provided. The non-volatile register file configuration circuit includes a selection circuitry and a plurality of nanotube fuse elements, each in electrical communication with one of a plurality of non-volatile register files.

Abstract: A method of resetting a resistive change memory element is disclosed. The method comprises performing a series of programming operations—for example, a programming pulse of a predetermined voltage level and pulse width—on a resistive change memory element in order to incrementally increase the resistance of the memory element above some predefined threshold. Prior to each programming operation, the resistive state of the memory element is measured and used to determine the parameters used in that programming operation. If this measured resistance value is above a first threshold value, the memory element is determined to already be in a reset state and no further programming operation is performed. If this measured resistance value is below a second threshold value, this second threshold value being less than the first threshold value, a first set of programming parameters are used within the programming operation.

Abstract: Nanotube-based switching elements and logic circuits are disclosed. Under one embodiment of the invention, a Boolean logic circuit includes at least one input terminal and an output terminal, and a network of nanotube switching elements electrically disposed between said at least one input terminal and said output terminal. The network of nanotube switching elements effectuates a Boolean function transformation of Boolean signals on said at least one input terminal. The Boolean function transformation includes a Boolean inversion within the function, such as a NOT or NOR function.

Abstract: A non-volatile memory cell includes a volatile storage device that stores a corresponding logic state in response to electrical stimulus; and a shadow memory device coupled to the volatile storage device. The shadow memory device receives and stores the corresponding logic state in response to electrical stimulus. The shadow memory device includes a non-volatile nanotube switch that stores the corresponding state of the shadow device.

Abstract: Physical neural networks based nanotechnology include dendrite circuits that comprise non-volatile nanotube switches. A first terminal of the non-volatile nanotube switches is able to receive an electrical signal and a second terminal of the non-volatile nanotube switches is coupled to a common node that sums any electrical signals at the first terminals of the nanotube switches. The neural networks further includes transfer circuits to propagate the electrical signal, synapse circuits, and axon circuits.

Abstract: Methods for passivating a carbonic nanolayer (that is, material layers comprised of low dimensional carbon structures with delocalized electrons such as carbon nanotubes and nano-scopic graphene flecks) to prevent or otherwise limit the encroachment of another material layer are disclosed. In some embodiments, a sacrificial material is implanted within a porous carbonic nanolayer to fill in the voids within the porous carbonic nanolayer while one or more other material layers are applied over or alongside the carbonic nanolayer. Once the other material layers are in place, the sacrificial material is removed. In other embodiments, a non-sacrificial filler material (selected and deposited in such a way as to not impair the switching function of the carbonic nanolayer) is used to form a barrier layer within a carbonic nanolayer. In other embodiments, carbon structures are combined with and nanoscopic particles to limit the porosity of a carbonic nanolayer.

Abstract: Under one aspect, a resonator 400 includes a nanotube element 410 including a non-woven fabric of unaligned nanotubes and having a thickness, and a support structure 404 defining a gap 406 over which the nanotube element 410 is suspended, the thickness of the nanotube element 410 and the length of the gap 406 being selected to provide a pre-specified resonance frequency for the resonator 400 The resonator 400 also includes a conductive element 412 in electrical contact with the nanotube element 410, a drive electrode 408 in spaced relation to the nanotube element 410, and power logic in electrical contact with die at least one drive electrode 408 The power logic provides a series of electrical pulses at a frequency selected to be about the same as the pre-specified resonance frequency of the resonator 400 to the drive electrode 408 during operation of the resonator 400, such that the nanotube element 410 responds to the series of electrical pulses applied to the drive electrode 408 by making a series of mecha

Abstract: Nanowire articles and methods of making the same are disclosed. A conductive article includes a plurality of inter-contacting nanowire segments that define a plurality of conductive pathways along the article. The nanowire segments may be semiconducting nanowires, metallic nanowires, nanotubes, single walled carbon nanotubes, multi-walled carbon nanotubes, or nanowires entangled with nanotubes. The various segments may have different lengths and may include segments having a length shorter than the length of the article. A strapping material may be positioned to contact a portion of the plurality of nanowire segments. The strapping material may be patterned to create the shape of a frame with an opening that exposes an area of the nanowire fabric. Such a strapping layer may also be used for making electrical contact to the nanowire fabric especially for electrical stitching to lower the overall resistance of the fabric.

Abstract: 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.

Abstract: Random access memory including nanotube switching elements. A memory cell includes first and second nanotube switching elements and an electronic memory. Each nanotube switching element includes conductive terminals, a nanotube article and control circuitry capable of controllably form and unform an electrically conductive channel between the conductive terminals. The electronic memory is a volatile storage device capable of storing a logic state in response to electrical stimulus. In certain embodiment the electronic memory has cross-coupled first and second inverters in electrical communication with the first and second nanotube switching elements. The cell can operate as a normal electronic memory, or can operate in a shadow memory or store mode (e.g., when power is interrupted) to transfer the electronic memory state to the nanotube switching elements. The device may later be operated in a recall mode where the state of the nanotube switching elements may be transferred to the electronic memory.

Abstract: Non-volatile field effect devices and circuits using same. A non-volatile field effect device includes a source, drain and gate with a field-modulatable channel between the source and drain. Each of the source, drain, and gate have a corresponding terminal. An electromechanically-deflectable, nanotube switching element is electrically positioned between one of the source, drain and gate and its corresponding terminal. The others of the source, drain and gate are directly connected to their corresponding terminals. The nanotube switching element is electromechanically-deflectable in response to electrical stimulation at two control terminals to create one of a non-volatile open and non-volatile closed electrical communication state between the one of the source, drain and gate and its corresponding terminal.

Abstract: A dynamic sense current supply circuit and an associated method for rapidly characterizing a resistive memory array is disclosed. In one embodiment, the disclosed circuit comprises a first and second dynamically programmable current mirror sub-circuit. Responsive to a bank of control signals, each dynamically programmable current mirror sub-circuit provides a dynamically adjustable current scaling factor. These scaling factors are used to scale a supplied reference current to generate a plurality of sense currents which can be used within a plurality of read operations on a resistive memory array. A digital circuit is also provided to sense and store the result of each read operation.

Abstract: Under one aspect, a field effect device includes a gate, a source, and a drain, with a conductive channel between the source and the drain; and a nanotube switch having a corresponding control terminal, said nanotube switch being positioned to control electrical conduction through said conductive channel. Under another aspect, a field effect device includes a gate having a corresponding gate terminal; a source having a corresponding source terminal; a drain having a corresponding drain terminal; a control terminal; and a nanotube switching element positioned between one of the gate, source, and drain and its corresponding terminal and switchable, in response to electrical stimuli at the control terminal and at least one of the gate, source, and drain terminals, between a first non-volatile state that enables current flow between the source and the drain and a second non-volatile state that disables current flow between the source and the drain.

Abstract: The invention comprises a carbon nanotube switch suitable for use in an integrated circuit structure and capable of being moved from a first position in a first plane in the switch to a second position in a second plane in the switch using approximately the same energy as required to move the switch from the second position back to the first position. The switch comprises a flexible carbon nanotube strip secured clamped at one end in a first plane in a switching chamber, and secured or clamped, at the opposite end of the carbon nanotube, in a second plane in the switching chamber, which is parallel to the first plane but spaced therefrom, to permit the central portion of the carbon nanotube strip to move in the chamber between a first position in the first plane and in electrical contact with one or more first electrodes and a second position in the second plane and in electrical contact with one or more second electrodes.

Abstract: Under one aspect, a method of cooling a circuit element includes providing a thermal reservoir having a temperature lower than an operating temperature of the circuit element; and providing a nanotube article in thermal contact with the circuit element and with the reservoir, the nanotube article including a non-woven fabric of nanotubes in contact with other nanotubes to define a plurality of thermal pathways along the article, the nanotube article having a nanotube density and a shape selected such that the nanotube article is capable of transferring heat from the circuit element to the thermal reservoir.