Electrical bistabilities and memory mechanisms of organic bistable devices based on colloidal ZnO quantum dot-polymethylmethacrylate polymer nanocomposites

Abstract

Transmission electron microscopy images showed that colloidal ZnO quantum dots (QDs) were distributed around the surface of a polymethylmethacrylate (PMMA) polymer. Current-voltage (I-V) measurements on the Al/colloidal ZnO QDs blended with PMMA polymer layer/indium-tin-oxide/glass devices at 300 K showed a current bistability. The maximum ON/OFF ratio of the current bistability for the organic bistable devices (OBDs) was as large as 5×104, and the cycling endurance time of the ON/OFF switching for the OBDs was above 105. The memory mechanisms of the fabricated OBDs are described on the basis of the I-V results.

Resistive switching of in situ polymerized polystyrene matrix copolymerized with alkanedienyl passivated Si nanoparticles

“…Second, the Si NPs' preparation process by top-down method is relatively simple in this study [10,11]. In addition, the surface of Si NPs can be more easily grafted or passivated with organic moieties by surface alkylation reaction than other metallic, ZnO, and iron oxide NPs [5][6][7][8]. The organic moiety attached to Si NPs can be used for further functionalities such as chemical incorporation of the Si NPs into polymer matrix like PS [2,3].…”

“…Meanwhile, conjugated polymers, which have conductivity in itself, also have been introduced in hope of endowing both memory function and active channel function at the same time [4,5]. Typically, overall conduction mechanism for organic resistive switching have been dominated by many aspects of Ohmic conduction, Schottky emission, thermionic emission, space charge-limited current (SCLC), tunneling current, ionic conduction, hopping conduction, and impurity conduction [5,6].…”

“…Typically, overall conduction mechanism for organic resistive switching have been dominated by many aspects of Ohmic conduction, Schottky emission, thermionic emission, space charge-limited current (SCLC), tunneling current, ionic conduction, hopping conduction, and impurity conduction [5,6]. Especially for the NPs based devices, the conduction mechanisms could determine digital switching or analog switching, i.e., gradual changing resistance or phenomena that could mimic adaptive synaptic mechanism of neuromorphic system [8,9].…”

“…Memory devices having polymeric layers including nanoparticles (NPs) for charge trapping have been introduced for decades in resistive switching memory device formats, which have showed reversible control of electronic resistivity [1][2][3][4][5][6][7]. The polymeric memories have implemented two stable resistance states governed by external electrical field for the data storage applications.…”

Hybrid phthalocyanine/lead sulphide nanocomposite for bistable memory switches

“…The device based upon a 180nm thick spin-coated hybrid layer of 6% wt of colloidal zinc oxide nanoparticles (18nm in size) in polyvinylpyrrolidone (PVP) sandwiched between the indium tin oxide substrate and aluminium top electrode displays non-volatile memory characteristics, giving on/off ratio of 3×10 3 [19]. Switches made of colloidal 5nm diameter ZnO QDs in polymethylmethacryalate (PMMA) within the similar electrode configuration, however, exhibit higher ratio by one order of magnitude [20] The filamentary conduction in a biopolymer silk protein film incorporating gold nanoparticles is found to be responsible for a high value of on/off ratio in the order of 10 6 [21]. Apart from the filamentary conduction model, a trap-filled limited conduction model has been developed using inorganic semiconducting nanoparticles as trapping centres whereas nanoparticles are regarded as being acceptor centres of electrons in the charge complex structure of a hybrid nanocomposite [22].…”