Negative differential resistance and resistive switching behaviors in Cu2S nanowire devices

Applied Physics Letters (Impact Factor: 3.3). 05/2010; 96(22). DOI: 10.1063/1.3442919


Two-terminal devices of Cu2S/ZnO core/shell nanowires were fabricated and measured. Forward bias sweeping produced a rectified I-V characteristic of a diode, with turn-on voltages varying from 150 to 300 mV. The turn-on voltages depended on the rate at which the bias was varied. When the bias scan was reversed, a resistive switching (RS) behavior was observed. A low-resistance state was measured, and the diode characteristic diminished. At -50 to -150 mV, negative differential resistance (NDR) was observed, after which the diode behavior was restored. This phenomenon was explained using the diffusion of Cu+ within Cu2S. ZnO acted to limit RS to the positive bias range and NDR to the negative bias range.

23 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: Memristive characteristics in semiconductor/metal contacts are studied by conductive atomic force microscopy. The ZnO/Au device shows excellent memristive characteristics under Pt and TiN tips and the resistances of the high-resistance state and the low-resistance state are almost unchanged with time. Unipolar resistive switching behaviour is observed when a positive voltage is applied. In addition, the pure Au film also shows resistive switching behaviour under the TiN tip which was used to test the ZnO/Au device, but this behaviour cannot be observed under a Pt tip. Our results suggest that the memristive characteristics existing in semiconductor/metal contacts are due to the formation of conducting filaments in the interior of the semiconductor and the change in the energy barrier at the interface between the conductive atomic force microscope tip and the ZnO film.
    Journal of Physics D Applied Physics 11/2011; 44(47):475102. DOI:10.1088/0022-3727/44/47/475102 · 2.72 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Using vertically aligned Cu(2)S nanowires as both physical templates and chemical sources, unique heteronanostructures were synthesized by solid-state conversion reactions at low temperatures. At temperatures as low as 105 degrees C and in the presence of H(2)S, segmented nanowires and rod-in-a-tube (RIT) structures were produced. The different morphologies were discovered to depend on the diffusivity of the ions from various metal coatings. In the case where the inward diffusion of outer metal is faster or roughly equivalent to that of Cu(+) outward diffusion, incorporation and subsequent phase segregation occurred to yield segmented nanowires; in instances where Cu(+) diffuses outward more quickly than the metal coating inward, the RIT morphology formed via a Kirkendall-like mechanism. The nanowire-Cu substrate interface was believed to play a unique and crucial role as either a reservoir of additional Cu or as a sink for out-diffusing Cu, depending on the nature of the reaction. Full conversion of Cu(2)S nanowires to wurtzite ZnS was also demonstrated, with the complete displacement of Cu back into the Cu substrate. These low-temperature, solid-state conversion reactions show promise as a possible route for synthesizing vertically aligned nanostructures with more complicated compositions.
    Chemistry of Materials 11/2011; DOI:10.1021/cm202564e · 8.35 Impact Factor
  • Source
    Microelectronics Journal 01/2012; 43(3):169-175. · 0.91 Impact Factor
Show more


23 Reads
Available from