Aspects of the subject disclosure may include, for example, applying a setting voltage across first and second electrodes, wherein a nanowire with a first electrical resistance is electrically connected between the first and second electrodes, wherein the applying of the setting voltage causes a migration of ions from the first and/or second electrodes to a surface of the nanowire, and wherein the migration of ions effectuates a reduction of electrical resistance of the nanowire from the first electrical resistance to a second electrical resistance that is lower than the first electrical resistance; and applying a reading voltage across the pair of electrodes, wherein the reading voltage is less than the setting voltage, and wherein the reading voltage is sufficiently small such that the applying of the reading voltage causes no more than an insignificant change of the electrical resistance of the nanowire from the second electrical resistance. Other embodiments are disclosed.

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.

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.

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.

Aspects of the subject disclosure may include, for example, applying a setting voltage across first and second electrodes, wherein a nanowire with a first electrical resistance is electrically connected between the first and second electrodes, wherein the applying of the setting voltage causes a migration of ions from the first and/or second electrodes to a surface of the nanowire, and wherein the migration of ions effectuates a reduction of electrical resistance of the nanowire from the first electrical resistance to a second electrical resistance that is lower than the first electrical resistance; and applying a reading voltage across the pair of electrodes, wherein the reading voltage is less than the setting voltage, and wherein the reading voltage is sufficiently small such that the applying of the reading voltage causes no more than an insignificant change of the electrical resistance of the nanowire from the second electrical resistance. Other embodiments are disclosed.

Aspects of the subject disclosure may include, for example, applying a setting voltage across first and second electrodes, wherein a nanowire with a first electrical resistance is electrically connected between the first and second electrodes, wherein the applying of the setting voltage causes a migration of ions from the first and/or second electrodes to a surface of the nanowire, and wherein the migration of ions effectuates a reduction of electrical resistance of the nanowire from the first electrical resistance to a second electrical resistance that is lower than the first electrical resistance; and applying a reading voltage across the pair of electrodes, wherein the reading voltage is less than the setting voltage, and wherein the reading voltage is sufficiently small such that the applying of the reading voltage causes no more than an insignificant change of the electrical resistance of the nanowire from the second electrical resistance. Other embodiments are disclosed.

Disclosed are systems and methods for performing efficient vector-matrix multiplication using a sparsely-connected conductance matrix and analog mixed signal (AMS) techniques. Metal electrodes are sparsely connected using coaxial nanowires. Each electrode can be used as an input/output node or neuron in a neural network layer. Neural network synapses are created by random connections provided by coaxial nanowires. A subset of the metal electrodes can be used to receive a vector of input voltages and the complementary subset of the metal electrodes can be used to read output currents. The output currents are the result of vector-matrix multiplication of the vector of input voltages with the sparsely-connected matrix of conductances.

Disclosed are systems and methods for performing efficient vector-matrix multiplication using a sparsely-connected conductance matrix and analog mixed signal (AMS) techniques. Metal electrodes are sparsely connected using coaxial nanowires. Each electrode can be used as an input/output node or neuron in a neural network layer. Neural network synapses are created by random connections provided by coaxial nanowires. A subset of the metal electrodes can be used to receive a vector of input voltages and the complementary subset of the metal electrodes can be used to read output currents. The output currents are the result of vector-matrix multiplication of the vector of input voltages with the sparsely-connected matrix of conductances.

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.

Under one aspect, a covered nanotube switch includes: (a) a nanotube element including an unaligned plurality of nanotubes, the nanotube element having a top surface, a bottom surface, and side surfaces; (b) first and second terminals in contact with the nanotube element, wherein the first terminal is disposed on and substantially covers the entire top surface of the nanotube element, and wherein the second terminal contacts at least a portion of the bottom surface of the nanotube element; and (c) control circuitry capable of applying electrical stimulus to the first and second terminals. The nanotube element can switch between a plurality of electronic states in response to a corresponding plurality of electrical stimuli applied by the control circuitry to the first and second terminals. For each different electronic state, the nanotube element provides an electrical pathway of different resistance between the first and second terminals.