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The solid-electrolyte-based memristors have attracted tremendous attention for the next-generation nonvolatile memory for both logic and neuromorphic applications. However, they encounter variability performance challenges which originated from the random ionic transport and conductive filaments formation. Evidently, the electrochemical metallized mechanism associated with ion transport has been elucidated. Nonetheless, the failure mechanism caused by ion transport during cycles is rarely reported. Hereafter, the five stages of failure in the Ag/Ag10Ge15Te75/W memristor are elucidated through ex-situ current-voltage measurements combined with in-situ transmission electron microscopy characteristics. Our investigation reveals that the migration and enrichment of Ag ions result in the precipitation of Ag2Te. The formation of Ag2Te hinders the device's ability to maintain its bipolar characteristics and also decreases the resistance value of the high resistance state, thereby reducing the device's switching ratio. The promising results provide important guidance for the future design of structures and the manipulation of ion transport for high-performance memristors. [ABSTRACT FROM AUTHOR]

The synapse is one of the fundamental elements in human brain performing functions such as learning, memorizing, and visual processing. The implementation of synaptic devices to realize neuromorphic computing and sensing tasks is a key step to artificial intelligence, which, however, has been bottlenecked by the complex circuitry and device integration. We report a high-performance charge-trapping memory synaptic device based on two-dimensional (2D) MoS2 and high-k Ta2O5–TiO2 (TTO) composite to build efficient and reliable neuromorphic system, which can be modulated by both electrical and optical stimuli. Significant and essential synaptic behaviors including short-term plasticity, long-term potentiation, and long-term depression have been emulated. Such excellent synaptic behaviors originated from the good nonvolatile memory performance due to the high density of defect states in the engineered TTO composite. The 2D synaptic device also exhibits effective switching by incident light tuning, which further enables pattern recognition with accuracy rate reaching 100%. Such experimental demonstration paves a robust way toward a multitask neuromorphic system and opens up potential applications in future artificial intelligence and sensing technology.

Organic field‐effect transistor (OFET) memory based on pentacene has attracted a lot of attentions due to its promising prospect of application in flexible electronics, while the high programming/erasing (P/E) gate voltages due to the existence of hole barrier at pentacene/polymer interface leaves great challenges for its commercial applications. A high‐performance pentacene‐based OFET nonvolatile memory (ONVM) with polymer blends is reported here as the charge‐trapping layer containing poly(2‐vinyl naphthalene) (PVN) and poly{[N,N'‐bis(2‐octyldodecyl)naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐alt‐5,5'‐(2,2'‐bithiophene)} (N2200). The presence of N2200, an n‐type semiconductor, in blends significantly improves the memory performance of pentacene‐based memory devices based on the static‐electric effect. The electrons in N2200 are aggregated near the pentacene/polymer interface due to the electric attraction from the positively charged defects in pentacene. Furthermore, those electrons reduce the height of hole barrier and produce local easy‐transportation paths for holes between pentacene and PVN, which enables the electret‐based ONVM device with low P/E voltages, fast P/E speeds, large mobility and stable multilevel data‐storage ability in ambient air. [ABSTRACT FROM AUTHOR]

The synapse is one of the fundamental elements in human brain performing functions such as learning, memorizing, and visual processing. The implementation of synaptic devices to realize neuromorphic computing and sensing tasks is a key step to artificial intelligence, which, however, has been bottlenecked by the complex circuitry and device integration. We report a high-performance charge-trapping memory synaptic device based on two-dimensional (2D) MoS2 and high-k Ta2O5–TiO2 (TTO) composite to build efficient and reliable neuromorphic system, which can be modulated by both electrical and optical stimuli. Significant and essential synaptic behaviors including short-term plasticity, long-term potentiation, and long-term depression have been emulated. Such excellent synaptic behaviors originated from the good nonvolatile memory performance due to the high density of defect states in the engineered TTO composite. The 2D synaptic device also exhibits effective switching by incident light tuning, which further enables pattern recognition with accuracy rate reaching 100%. Such experimental demonstration paves a robust way toward a multitask neuromorphic system and opens up potential applications in future artificial intelligence and sensing technology. [ABSTRACT FROM AUTHOR]

Theoretical and experimental work has revealed that a positively charged insulator layer formed by oxygen‐related defects near pentacene–dielectric interface in organic field‐effect‐transistors (OFETs) severely affects their performance. A novel OFET memory structure with an n‐type organic buffer layer at the pentacene/polymer interface is proposed. In this structure, electrons are induced on the surface of the n‐type organic layer near the interface due to the electrostatic field of the positively charged insulator and partly compensate the local positive charges at the interface, leading to a reduction in the height of hole barrier formed at the interface. On the other hand, the positive space charges will be induced in an extended region in n‐type organic layer due to the limited density of ionized donors, blocking the back transfer of holes to pentacene as a result of the thicker positively charged layer. This idea is implemented in the n‐type PTCDI‐C13‐buffered OFETs with poly(2‐vinyl naphthalene) (PVN) dielectric, in which greatly reduced P/E gate voltages, reliable P/E endurance of more than 10 000 cycles, and excellent retention time of more than 104 s with an ION/IOFF of more than 104 under a set of P/E pulses with low amplitudes and short pulses are achieved in air. [ABSTRACT FROM AUTHOR]

In this work, we have fabricated and thoroughly characterized dielectric-stacked memory devices with AlO-CuO composites as the charge trapping layer which are prepared by using atomic layer deposition and RF-magnetron sputtering techniques. The devices exhibit a large memory window of 13.27 V and a density of the trapped charges of 9.37 × 10 cm at a working voltage of ±11 V. The microstructural observations by using high resolution transmission electron microscopy and the analysis on X-ray photoelectron spectroscopy indicate that the strong charge-trapping ability of AlO-CuO composite should be ascribed to the occurrence of Cu, resulted by the inter-diffusion at the interface of CuO/AlO. Such an interesting composite layer has very attractive application in nonvolatile memory. [ABSTRACT FROM AUTHOR]

An effective method to generate traps at the interface was developed to enhance the charge trapping capability of HfO2/Al2O3 multilayered memory devices. A high charge density was obtained in the inter-diffusion layer in which additional trap sites could be created by thermal-treatment induced inter-diffusion. By keeping the consistent thickness of the charge trapping layer and increasing the number of the inter-diffusion layers, more traps can be introduced in the charge trapping layer. So, creating more trap sites by enhancing the inter-diffusion at the interface of different high-k dielectrics could be a potential choice for future memory applications. [ABSTRACT FROM AUTHOR]

High‐performance bottom‐gate nonvolatile organic field‐effect transistor (OFET) devices based on a special matching energy‐band alignment between the organic semiconductor pentacene and the charge‐trapping dielectric ZnTe are reported. The lower potential difference between the conduction band minimum of ZnTe and the lowest unoccupied molecular orbital of pentacene with a weak electron conductivity endows the OFET a memory window of 10 V at an applied sweeping gate‐voltage of ±15 V, a high ION/IOFF ratio of more than 106, and good retention with a high ION/IOFF ratio of 6 × 105 after 104 s. The large memory window of the OFET is attributed to the unique energy‐band alignment of the memory device and the high density of traps in Te‐deficient ZnTe film, and the prominent retention is attributed to the deeply trapped electrons in the potential well formed by Al2O3 tunneling and blocking layers. [ABSTRACT FROM AUTHOR]