Light-modulated transparent memristors combining photoresponse and data storage are promising as multifunctional devices. Herein, a multicolor light-modulated transparent memristor based on black phosphorous (BP) is designed, fabricated, and investigated. BP is a class of emerging two-dimensional (2D) materials with a natural direct band gap and a broad light absorption. Herein, BP nanosheets (BP@PS NSs) coated with polystyrene (PS) are prepared and serve as the resistive switching (RS) layer in the ITO/BP@PS/ITO memristor, which shows >75% transmittance between 350 and 1100 nm. With the aid of PS, the BP@PS-based memristor has excellent RS characteristics such as no initial preforming, low operating voltage, and long retention time. According to the energy band model, the RS mechanism of the high and low resistance states contributes to the transformation from ohmic contact to Schottky contact. During light illumination ranging from ultraviolet (380 nm) to near infrared (785 nm), the Schottky barrier height is elevated further so that the resetting voltages and power consumption decrease. Moreover, the ON/OFF ratios are improved and the maximum enhancement is demonstrated to be more than 10 times. BP is a promising RS material in light-modulated memristors, and the novel device configuration provides insights into the development of multifunctional microelectronic devices based on 2D materials.

using artificial synapses is an essential step to accomplish the neuromorphic computing system. [9,10] Formerly, artificial synapses were realized by complementary metal-oxide-semiconductor (CMOS) circuitry containing dozens of electronic components. [11] However, many electronic components result in complicated architecture and high energy consumption. As comparison, two-terminal memristors, especially resistive random access memory and phase change random access memory, that recently entered our field of vision have been widely discussed as artificial synapses owing to their structures which is similar to that of synapses and the reproducible tuning of resistance. [12][13][14][15][16] Also, for an ideal synapse device it is better to meet these requirements, such as symmetric potentiation-depression characteristics, 5-bit/cell analog levels, and high non-volatility with ≈100 conductance ON/OFF ratio. They are the key points we need to take into account. [17,18] In particular, HfO 2 -based memristors have been demonstrated as a leading alternative as synapse in virtue of its distinctive superiority, such as simple structure, <10 ns switching speed, <10 pJ power consumption, multilevel ability, and compatibility with CMOS fabrication process. [19][20][21] However, the resistance contrast (ON/OFF ratio) of HfO 2 -based memristors ranges from ≈40 to ≈150. [22] Considering the resistance fluctuation of these memristors across a silicon wafer, larger ON/OFF ratio is needed to guarantee high recognition accuracy (>97%). [23] Recently, several works were reported on improvement of the memristors' performance with thin interfacial layer. [24][25][26] As one of the most important multiferroic materials, bismuth iron oxide with perovskite structure has come into notice for its potential in multifunctional device applications. [27] Moreover, BiFeO 3 (BFO) has attracted much attention because it possesses superior characteristics of resistance switching (RS) such as large ON/OFF ratio in some researches. [28] It is also confirmed that BFO can be applied in bi-layer design memristor to significantly improve RS characteristics, [29] which gives inspiration to insert BFO thin film as the goal of high device performances.In this work, ultrathin BFO film was inserted to fabricate Pt/BFO/HfO 2 /TiN memristor to improve the RS characteristic of HfO 2 -based memristor. The material characterization and RS behavior were systemically analyzed. The role of the inserting BFO layer on the RS behavior was evaluated and the RS mechanism triggered by inserting BFO film was explored.HfO 2 -based memristors that remembers the history of the current that has passed through them have attracted great interest for use as artificial synapses in neuromorphic systems. However, the low resistance contrast exhibited by HfO 2 -based memristors seriously decreases their recognition accuracy. By inserting a 2 nm BiFeO 3 layer a large memory window of 10 4 and remarkable pulse endurance of 10 8 cycles are achieved. Multilevel storage capability is also d...

Recently, neuromorphic devices have attracted great attention in the field of artificial intelligence technology at the hardware level. In particular regarding the developments of flexible electronics, there is an increasing interest in brain‐inspired multi‐functional perception learning system. In the present work, flexible cognitive memristors based on poly(vinyl alcohol)–graphene oxide (PVA‐GO) hybrid nanocomposite are proposed. These devices exhibit excellent electrical performance at ultralow voltage below 0.5 V with high stability against mechanical stress. The threshold voltage of resistance switching is as low as ≈0.2 V. Good endurance and stability are observed. Most importantly, the PVA‐GO‐hybrid‐based memristor demonstrates an ultralow power consumption of ≈0.5 µW during the SET process. Moreover, such cognitive memristor‐based neuron circuits demonstrate Pavlovian‐associative learning behaviors. These memristors have potential applications in ultralow‐power multi‐functional perception learning systems.

A highly efficient type-II 2D heterostructure for photocatalytic water splitting.

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