Negative differential resistance and resistive switching behaviors in Cu2S nanowire devices

Applied Physics Letters (Impact Factor: 3.52). 05/2010; 96(22). DOI: 10.1063/1.3442919

ABSTRACT 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.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Memristive behavior is found in nanoscale contact between conductive atomic force tip and ZnO/Au device, which is fabricated by molecular beam epitaxy. Stable resistive switching behaviors can be repeated for hundreds of times. The resistance ratio of high-resistance state to low-resistance state can be up to 100 times. The memristive behaviors could persist for months, but the switching voltage for several special points could change with time resulting from the metal atoms permeating or the decreasing of oxygen vacancies. The memristive characteristics could be explained by the changing of interface barrier between the conductive atomic force tip and the ZnO film. Especially, an idealized model is formulated based on the device structure to study the memristive characteristics, and the calculated result is consistent with the present experiment.
    IEEE Transactions on Nanotechnology 11/2012; 11(6):1135-1139. DOI:10.1109/TNANO.2012.2214486 · 1.62 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The excellent memristive behavior of ZnO-based devices with embedded Ti nano-layers is obtained. The results show that inserting Ti layers can effectively reduce the switching voltages and increase the R (off)/R (on) ratio (more than 10(3)). In particular, the stable switching properties is obtained by introducing 2.5 nm Ti layer, and the devices show good sweep endurance (about 320 cycles) and a long retention time of more than 10(6) s as compared with the devices without Ti layer. A model combining the redox reaction and the oxygen vacancy-based conducting filament is proposed to explain the memory effect. The conducting filament will be formed and ruptured along fixed paths at a certain region due to the non-uniform distribution of oxygen vacancies, which is responsible for the improvement of device performance.
    Applied Physics A 07/2014; 116(1):1-7. DOI:10.1007/s00339-014-8450-z · 1.69 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: CuS/PbS p-n heterojunction nanowires arrays have been successfully synthesized. Association of template and DC power sources by controllable electrochemistry processes offers a technique platform to efficiently grow a combined heterojunction nanowire arrays driven by a minimization of interfacial energy. The resulting p-n junction materials of CuS/PbS show highly uniform 1D wire architecture. The single CuS/PbS p-n heterojunction nanowire based devices were fabricated, and their electrical behaviors were investigated. The independent nanowires exhibited a very high ON/OFF ratio of 1195, due to the association effect of electrical switches and diodes.
    Inorganic Chemistry 06/2012; 51(12):6771-5. DOI:10.1021/ic300471j · 4.79 Impact Factor