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A central issue of nanoelectronics concerns their fundamentalscaling limits, that is, the smallest and most energy-efficient devicesthat can function reliably. Unlike charge-based electronics that areprone to leakage at nanoscale dimensions, memory devices based onphase change materials (PCMs) are more scalable, storing digital informationas the crystalline or amorphous state of a material. Here, we describea novel approach to self-align PCM nanowires with individual carbonnanotube (CNT) electrodes for the first time. The highly scaled andspatially confined memory devices approach the ultimate scaling limitsof PCM technology, achieving ultralow programming currents (∼0.1μA set, ∼1.6 μA reset), outstanding on/off ratios(∼103), and improved endurance and stability atfew-nanometer bit dimensions. In addition, the powerful yet simplenanofabrication approach described here can enable confining and probingmany other nanoscale and molecular devices self-aligned with CNT electrodes. [ABSTRACT FROM AUTHOR]

Integration of nanowires into functional devices withhigh yieldsand good reliability turned out to be a lot more challenging and provedto be a critical issue obstructing the wide application of nanowire-baseddevices and exploitation of their technical promises. Here we demonstratea relatively easy macrofabrication of a nanowire-based imaging circuitryusing a recently developed nanofabrication technique. Extremely longand polymer encapsulated semiconducting nanowire arrays, mass-producedusing the iterative thermal drawing, facilitate the integration process;we manually aligned the fibers containing selenium nanowires overa lithographically defined circuitry. Controlled etching of the encapsulatingpolymer revealed a monolayer of nanowires aligned over an area of1 cm2containing a 10 × 10 pixel array. Each light-sensitivepixel is formed by the contacting hundreds of parallel photoconductivenanowires between two electrodes. Using the pixel array, alphabeticcharacters were identified by the circuitry to demonstrate its imagingcapacity. This new approach makes it possible to devise extremelylarge nanowire devices on planar, flexible, or curved substrates withdiverse functionalities such as thermal sensors, phase change memory,and artificial skin. [ABSTRACT FROM AUTHOR]

The self-assembly of Ge1Sb2Te4nanowires (NWs) for phase change memories application wasachievedby metal organic chemical vapor deposition, catalyzed by Au nanoislandsin a narrow range of temperatures and deposition pressures. In theoptimized conditions of 400 °C, 50 mbar, the NWs are Ge1Sb2Te4single hexagonal crystals. Phase changememory switching was reversibly induced by nanosecond current pulsesthrough metal-contacted NWs with threshold voltage of about 1.35 V. [ABSTRACT FROM AUTHOR]