Numerical simulation study of organic nonvolatile memory with polysilicon floating gate

A polysilicon-based organic nonvolatile floating-gate memory device with a bottom-gate top-contact configuration is investigated,in which polysilicon is sandwiched between oxide layers as a floating gate.Simulations for the electrical characteristics of the polysilicon floating gate-based memory device are performed.The shifted transfer characteristics and corresponding charge trapping mechanisms during programing and erasing（P/E） operations at various P/E voltages are discussed.The simulated results show that present memory exhibits a large memory window of 57.5 V,and a high read current on/off ratio of ≈ 10~3.Compared with the reported experimental results,these simulated results indicate that the polysilicon floating gate based memory device demonstrates remarkable memory effects,which shows great promise in device designing and practical application.

Multi-polar resistance switching and memory effect in copper phthalocyanine junctions

Copper phthalocyanine junctions, fabricated by magnetron sputtering and evaporating methods, show multi-polar （unipolar and bipolar） resistance switching and the memory effect. The multi-polar resistance switching has not been observed simultaneously in one organic material before. With both electrodes being cobalt, the unipolar resistance switching is universal. The high resistance state is switched to the low resistance state when the bias reaches the set voltage. Generally, the set voltage increases with the thickness of copper phthalocyanine and decreases with increasing dwell time of bias. Moreover, the low resistance state could be switched to the high resistance state by absorbing the phonon energy. The stability of the low resistance state could be tuned by different electrodes. In Au/copper phthalocyanine/Co system, the low resistance state is far more stable, and the bipolar resistance switching is found. Temperature dependence of electrical transport measurements demonstrates that there are no obvious differences in the electrical transport mechanism before and after the resistance switching. They fit quite well with Mott variable range hopping theory. The effect of A1203 on the resistance switching is excluded by control experiments. The holes trapping and detrapping in copper phthalocyanine layer are responsible for the resistance switching, and the interfacial effect between electrodes and copper phthalocyanine layer affects the memory effect.

Flexible multi-level quasi-volatile memory based on organic vertical transistor

Driven by important megatrends such as cloud computing,artificial intelligence,and the Internet of Things,as a device used to store programs and data in computing systems,memory is struggling to catch up with the explosive growth of data and bandwidth requirements in the system.However,the storage wair between non-volatile memory and volatile memory retards the further improvement of modern memory computing systems.Herein,a quasi-volatile transistor memory based on organic polymer/perovskite quantum dot blend was fabricated using the vertical transistor configuration.Contributing to vertical structure and appropriate doping ratio of blend film,the quasi-volatile memory device displayed 1,560 times longer data retention time(>100 s)with respect to the dynamic random access memory and fast data programming speed(20 ps)in which was far more quickly than that of other organic non-volatile memories to fill the gap between volatile and non-volatile memories.Moreover,the device retention characteristics could be further promoted under the photoelectric synergistic stimulation,which also provided the possibility to reduce electric writing condition.Furthermore,the quasi-volatile memory device showed good electrical performance under bending conditions.This work provides a simple solution to fabricate multi-level quasi-volatile memory,which opens up a whole new avenue of"universal memory"and lays a solid foundation for low power and flexible random access memory devices.