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The composite of zinc oxide (ZnO) and polyurethane (PU) was used as an active layer. The conductance quantization was demonstrated in nonvolatile resistive switching memory devices of the indium tin oxide/PU + ZnO/Al sandwich structure. The observed bipolar resistive switching behavior is estimated to arise from the formation and dissolution of Zn filaments. Furthermore, conductance quantization with both integer and half-integer multiples of G0(2e2/h, where eis electron charge and his Planck’s constant) has been observed in which multilevel conductance steps are separated by half-integer multiples of G0. The observed quantized conductance phenomena in multiple well-circumscribed resistance states were appropriate for application in multilevel data memory cells.

Bistable nonvolatile memory devices with resistive switching characteristics were fabricated based on polyurethane (PU) mixing with 2-(4-tert-butylphenyl)-5-(4-biphenylyl)-1,3,4-oxadiazole (PBD). The indium tin oxide/PU+PBD/aluminum device exhibited nonvolatile electrical bistable flash memory behavior with an ON/OFF state current ratio greater than 103. It has been demonstrated that the resistive switching characteristics in the memory device were strongly dependent on the treatment of the polymer blend by PBD. The additive of PBD in PU film reduced the current in the OFF-state significantly and improved the performance of device with the ON/OFF current ratio increased by 2 orders of magnitude, and ON and OFF states of the device can be maintained over 5 h without deterioration.

Multilevel data memory and artificial synaptic plasticity in poly(vinylidene fluoride-co-trifluoroethylene) [P(VDF-TrFE)] ferroelectric field effect transistors were demonstrated. The dynamics of ferroelectric polarization transformation modulate potential of transistor channel, and adjust the electric field of the P(VDF-TrFE) ferroelectric film by potential along channel direction, thus realizing the multilevel nonvolatile memory state. The artificial synaptic plasticity of transistor is simulated, and the long-term plasticity of excited/inhibited postsynaptic current, paired impulse facilitation/inhibition, and spike-rate-dependent plasticity is realized. In long-term potentiation/depression simulation of devices, the conductivity symmetry and linearity are improved by setting the amplitude of the pulse increments. In addition, the vector-matrix multiplication operation was performed in a crossbar array. This work demonstrates the scheme to develop the P(VDF-TrFE) transistors-based multilevel memory and neural morphological computing.

The broken processes of carbon-rich conducting filament have been clarified in composite of [6, 6]-phenyl C61-butyric acid methyl ester (PCBM) and poly(4-vinyl phenol) (PVP) based resistive memory devices. Here, the multistage resistive switching processes in Al/PCBM + PVP/Al sandwich construction were reported, which exhibits a typical nonvolatile WORM storage effect, and these several states are well separated by a resistance ratio of 1: (5.01 × 101): (2.08 × 102): (5.45 × 102): (2.42 × 103). The Al/PCBM + PVP/Al memory devices feature multistate data storage, long retention time (1 × 105s), and large memory window (maximum ON/OFF ratio, ∼104). Furthermore, conductance quantization during resistive switching processes was analyzed. This work might promote and improve the understanding and awareness of resistive switching mechanism for organic-based memory devices.

WO3 Nano powders had been synthesized by hydrothermal synthesis through acidification of Na2WO4*2H2O at different PH value. The phase and morphology of WO3 nano powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), respectively. The result showed that PH value effect the phase and morphology of WO3 nano powders. The morphology of WO3 was nanoparticles at PH=1, however became nanosheets at PH=2. The effect of PH value on the morphology of WO3 nano powders was studied. NH3 gas sensing properties of WO3 nano powders were also studied. The result showed that WO3 nanosheets enhanced NH3 sensing performance to low concentration of NH3.

Two types of memory devices of ITO/methacrylate epoxy resin (MER)/Al and ITO/graphene/MER/Al have been fabricated. And the reset failure phenomena are observed in ITO/MER/Al devices on account of an unexpected negative-set that occasionally appeared in the reset process. The negative-set resistive switching behavior and reset failure phenomenon have been successfully eliminated by adding a graphene blocking layer. In addition, the ITO/graphene/MER/Al device shows satisfying resistive switching performances, including large on/off ratio and long retention time. The experiment result shows that the "pool" of active atoms in the counter electrode offer the cations source lead to the negative-set behavior in the ITO/MER/Al device.