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Reversible alternation between bipolar and unipolar resistive switching (RS) modes was observed by controlling voltage-polarity in Ag/MoS2/Au memory on polyethylene terephthalate (PET) substrate. The temperature-dependent low-resistance-state and Raman measurement indicated that Ag and sulphur vacancy (Vs)-based conductive filaments (CFs) were responsible for these two RS modes. The two kinds of CFs had different responses under positive read voltages. Thus, a new operation scheme of multilevel memory was demonstrated in which multiple states were distinguished by CF composition rather than resistance values. The memory capacity of the cell could be further extended by adjustments in CFs’ size in each mode. The RS performance of the device did not degrade under bending conditions even over 104 bending cycles, which indicated good mechanical flexibility. The present Ag/MoS2/Au memory has promise for future high-density flexible information storage. [ABSTRACT FROM AUTHOR]

We studied the influence of sp2 clustering on resistive switching uniformity in Cu/amorphous carbon/Pt electrochemical metallization memory. Herein, a simple method was utilized to adjust the degree of sp2 clustering by changing compliance currents (CCs). The small sp2 clusters within the a-C layer were found to condense into larger clusters with increasing CCs because of the CC-dependent Joule heating effect. Raman spectra experimentally verified the increase of sp2 cluster diameter with increasing CCs. Importantly, a switching uniformity improvement can be obtained by increasing the degree of sp2 clustering. The enhanced local electric field around sp2 clusters can account for the reduction of the Cu conductive filament randomness and corresponding improvement of memory performance. [ABSTRACT FROM AUTHOR]

p-GaN/i-Al2O3/n-ZnO (PIN) heterojunction LEDs with different dielectric Al2O3 thicknesses were fabricated via an atomic layer deposition technique. By optimizing the i-Al2O3 layer thickness to be ∼12 nm, the effective electron accumulation and hole injection are simultaneously achieved in the n-ZnO active layer, resulting in a greatly improved near-UV electroluminescence intensity of this PIN type LED. Moreover, by introducing Ag nanowires, whose surface plasmon (SP) resonant energy is closer to the ZnO UV emission energy, into the LED structure, the electroluminescence intensity was further increased ∼2.8 times. Time-resolved and temperature-dependent spectroscopy analyses reveal that both the spontaneous radiation rate and internal quantum efficiency of the ZnO active layer are increased as a result of resonant couplings between ZnO excitons and Ag nanowire SPs, which gives rise to the observed near-UV electroluminescence enhancement. [ABSTRACT FROM AUTHOR]