Abstract: Under one aspect, a non-volatile nanotube diode device includes first and second terminals; a semiconductor element including a cathode and an anode, and capable of forming a conductive pathway between the cathode and anode in response to electrical stimulus applied to the first conductive terminal; and a nanotube switching element including a nanotube fabric article in electrical communication with the semiconductive element, the nanotube fabric article disposed between and capable of forming a conductive pathway between the semiconductor element and the second terminal, wherein electrical stimuli on the first and second terminals causes a plurality of logic states.

Abstract: A non-volatile nanotube switch and memory arrays constructed from these switches are disclosed. A non-volatile nanotube switch includes a conductive terminal and a nanoscopic element stack having a plurality of nanoscopic elements arranged in direct electrical contact, a first comprising a nanotube fabric and a second comprising a carbon material, a portion of the nanoscopic element stack in electrical contact with the conductive terminal. Control circuitry is provided in electrical communication with and for applying electrical stimulus to the conductive terminal and to at least a portion of the nanoscopic element stack. At least one of the nanoscopic elements is capable of switching among a plurality of electronic states in response to a corresponding electrical stimuli applied by the control circuitry to the conductive terminal and the portion of the nanoscopic element stack. For each electronic state, the nanoscopic element stack provides an electrical pathway of corresponding resistance.

Abstract: Methods for reading and programming one or more resistive change elements within a 1-R resistive change element array are disclosed. These methods include using measurement and storage elements to measure the electrical response of one or more selected cells within an array and then comparing that stored electrical response to the electrical response of a reference element within the array to determine the resistive state of the one or more selected cells. These methods also include programming methods wherein selectable current limiting elements are used to permit or inhibit programming currents from flowing through selected and unselected cells, respectively. These methods further include programming methods that use specific biasing of array lines to provide sufficient programming currents through only selected cells.

Abstract: An improved switching material for forming a composite article over a substrate is disclosed. A first volume of nanotubes is combined with a second volume of nanoscopic particles in a predefined ration relative to the first volume of nanotubes to form a mixture. This mixture can then be deposited over a substrate as a relatively thick composite article via a spin coating process. The composite article may possess improved switching properties over that of a nanotube-only switching article. A method for forming substantially uniform nanoscopic particles of carbon, which contains one or more allotropes of carbon, is also disclosed.

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: Under one aspect, a non-volatile nanotube diode device includes first and second terminals; a semiconductor element including a cathode and an anode, and capable of forming a conductive pathway between the cathode and anode in response to electrical stimulus applied to the first conductive terminal; and a nanotube switching element including a nanotube fabric article in electrical communication with the semiconductive element, the nanotube fabric article disposed between and capable of forming a conductive pathway between the semiconductor element and the second terminal, wherein electrical stimuli on the first and second terminals causes a plurality of logic states.

Abstract: Nanotube films and articles and methods of making the same are disclosed. A conductive article or a substrate comprises at least two unaligned nanotubes extending substantially parallel to the substrate and each contacting end points of the article but each unaligned relative to the other, the nanotubes providing a conductive pathway within a predefined space.

Abstract: Methods for passivating a nanotube fabric layer within a nanotube switching device to prevent or otherwise limit the encroachment of an adjacent material layer are disclosed. In some embodiments, a sacrificial material is implanted within a porous nanotube fabric layer to fill in the voids within the porous nanotube fabric layer while one or more other material layers are applied adjacent to the nanotube fabric layer. 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 nanotube fabric layer) is used to form a barrier layer within a nanotube fabric layer. In other embodiments, individual nanotube elements are combined with and nanoscopic particles to limit the porosity of a nanotube fabric layer.

Abstract: Solutions of carbon nanotubes and methods for purifying the solutions are provided. The methods include mixing, for example, at least one complexing agents, at least one ionic species, and/or at least one buffer oxide etch (BOE) with a liquid medium containing carbon nanotubes and different types of contaminants, such as metal impurities, amorphous carbon, and/or silica particles, and performing a filtration process to the liquid medium so as to remove or reduce the contaminants in the liquid medium. As a result, carbon nanotube solutions of low contaminants are produced. In some embodiments, the solutions of this disclosure include a high concentration of carbon nanotubes and are substantially free from metal, amorphous carbon, and/or silica impurities.

Abstract: The present disclosure is directed toward carbon based diodes, carbon based resistive change memory elements, resistive change memory having resistive change memory elements and carbon based diodes, methods of making carbon based diodes, methods of making resistive change memory elements having carbon based diodes, and methods of making resistive change memory having resistive change memory elements having carbons based diodes. The carbon based diodes can be any suitable type of diode that can be formed using carbon allotropes, such as semiconducting single wall carbon nanotubes (s-SWCNT), semiconducting Buckminsterfullerenes (such as C60 Buckyballs), or semiconducting graphitic layers (layered graphene). The carbon based diodes can be pn junction diodes, Schottky diodes, other any other type of diode formed using a carbon allotrope. The carbon based diodes can be placed at any level of integration in a three dimensional (3D) electronic device such as integrated with components or wiring layers.

Abstract: Under one aspect, a non-volatile nanotube diode device includes first and second terminals; a semiconductor element including a cathode and an anode, and capable of forming a conductive pathway between the cathode and anode in response to electrical stimulus applied to the first conductive terminal; and a nanotube switching element including a nanotube fabric article in electrical communication with the semiconductive element, the nanotube fabric article disposed between and capable of forming a conductive pathway between the semiconductor element and the second terminal, wherein electrical stimuli on the first and second terminals causes a plurality of logic states.

Abstract: Inverter circuits and NAND circuits comprising nanotube based FETs and methods of making the same are described. Such circuits can be fabricating using field effect transistors comprising a source, a drain, a channel region, and a gate, wherein the first channel region includes a fabric of semiconducting nanotubes of a given conductivity type. Such FETs can be arranged to provide inverter circuits in either two-dimension or three-dimensional (stacked) layouts. Design equations based upon consideration of the electrical characteristics of the nanotubes are described which permit optimization of circuit design layout based upon constants that are indicative of the current carrying capacity of the nanotube fabrics of different FETs.

Abstract: Devices and methods for determining resistive states of resistive change elements in resistive change element arrays are disclosed. According to some aspects of the present disclosure the devices and methods for determining resistive states of resistive change elements can determine resistive states of resistive change elements by sensing current flow. According to some aspects of the present disclosure the devices and methods for determining resistive states of resistive change elements can determine resistive states of resistive change elements without the need for in situ selection devices or other current controlling devices. According to some aspects of the present disclosure the devices and methods for determining resistive states of resistive change elements can reduce the impact of sneak current when determining resistive states of resistive change elements.

Abstract: Devices and methods for determining resistive states of resistive change elements in resistive change element arrays are disclosed. According to some aspects of the present disclosure the devices and methods for determining resistive states of resistive change elements can determine resistive states of resistive change elements by sensing current flow. According to some aspects of the present disclosure the devices and methods for determining resistive states of resistive change elements can determine resistive states of resistive change elements without the need for in situ selection devices or other current controlling devices. According to some aspects of the present disclosure the devices and methods for determining resistive states of resistive change elements can reduce the impact of sneak current when determining resistive states of resistive change elements.

Abstract: Under one aspect, a method of making a nanotube switch includes: providing a substrate having a first conductive terminal; depositing a multilayer nanotube fabric over the first conductive terminal; and depositing a second conductive terminal over the multilayer nanotube fabric, the nanotube fabric having a thickness, density, and composition selected to prevent direct physical and electrical contact between the first and second conductive terminals. In some embodiments, the first and second conductive terminals and the multilayer nanotube fabric are lithographically patterned so as to each have substantially the same lateral dimensions, e.g., to each have a substantially circular or rectangular lateral shape. In some embodiments, the multilayer nanotube fabric has a thickness from 10 nm to 200 nm, e.g., 10 nm to 50 nm. The structure may include an addressable diode provided under the first conductive terminal or deposited over the second terminal.

Abstract: A high-speed memory circuit architecture for arrays of resistive change elements is disclosed. An array of resistive change elements is organized into rows and columns, with each column serviced by a word line and each row serviced by two bit lines. Each row of resistive change elements includes a pair of reference elements and a sense amplifier. The reference elements are resistive components with electrical resistance values between the resistance corresponding to a SET condition and the resistance corresponding to a RESET condition within the resistive change elements being used in the array. A high speed READ operation is performed by discharging one of a row's bit lines through a resistive change element selected by a word line and simultaneously discharging the other of the row's bit lines through of the reference elements and comparing the rate of discharge on the two lines using the row's sense amplifier. Storage state data are transmitted to an output data bus as high speed synchronized data pulses.

Abstract: A method for improving the stability of a resistive change cell is disclosed. The stability of a resistive change memory cell-that is, the tendency of the resistive change memory cell to retain its programmed resistive state-may, in certain applications, be compromised if the cell is programmed into an unstable or metastable state. In such applications, a programming method using bursts of sub-pulses within a pulse train is used to drive the resistive change cell material into a stable state during the programming operation, reducing resistance drift over time within the cell.

Abstract: The present disclosure is directed toward carbon based diodes, carbon based resistive change memory elements, resistive change memory having resistive change memory elements and carbon based diodes, methods of making carbon based diodes, methods of making resistive change memory elements having carbon based diodes, and methods of making resistive change memory having resistive change memory elements having carbons based diodes. The carbon based diodes can be any suitable type of diode that can be formed using carbon allotropes, such as semiconducting single wall carbon nanotubes (s-SWCNT), semiconducting Buckminsterfullerenes (such as C60 Buckyballs), or semiconducting graphitic layers (layered graphene). The carbon based diodes can be pn junction diodes, Schottky diodes, other any other type of diode formed using a carbon allotrope. The carbon based diodes can be placed at any level of integration in a three dimensional (3D) electronic device such as integrated with components or wiring layers.

Abstract: A non-volatile nanotube switch and memory arrays constructed from these switches are disclosed. A non-volatile nanotube switch includes a conductive terminal and a nanoscopic element stack having a plurality of nanoscopic elements arranged in direct electrical contact, a first comprising a nanotube fabric and a second comprising a carbon material, a portion of the nanoscopic element stack in electrical contact with the conductive terminal. Control circuitry is provided in electrical communication with and for applying electrical stimulus to the conductive terminal and to at least a portion of the nanoscopic element stack. At least one of the nanoscopic elements is capable of switching among a plurality of electronic states in response to a corresponding electrical stimuli applied by the control circuitry to the conductive terminal and the portion of the nanoscopic element stack. For each electronic state, the nanoscopic element stack provides an electrical pathway of corresponding resistance.

Abstract: An improved switching material for forming a composite article over a substrate is disclosed. A first volume of nanotubes is combined with a second volume of nanoscopic particles in a predefined ration relative to the first volume of nanotubes to form a mixture. This mixture can then be deposited over a substrate as a relatively thick composite article via a spin coating process. The composite article may possess improved switching properties over that of a nanotube-only switching article. A method for forming substantially uniform nanoscopic particles of carbon, which contains one or more allotropes of carbon, is also disclosed.