Memtransistor is a multiterminal device combining the concepts of memristor and field-effect transistor with two-dimensional (2D) materials. The gate tunability of resistive switching in 2D memtransistor enables the multifunctional modulation and promising applications in neuromorphic network. However, the tunability of switching ratio in 2D memtransistor remains small and seriously limits its practical application. Here, we investigate a memtransistor based on a 3-layer MoS2 and realize the electric, light, and their combined modulations. In the electric gate mode, switching ratio is tunable in a large scale in the range 100–105. In the light gate mode, a maximum conductance change of 450% can be obtained by increasing the light power. Moreover, the switching ratio can be further improved to ∼106 through a combination of electric and light dual gating. Such a gating effect can be ascribed to the modulation of carrier density in the MoS2 channel. Our work provides a simple approach for achieving a high-performance multifunctional memtransistor.

Spin-dependent charge transport, along with the potential electronic applications, is investigated in chiral 2D iodide hybrid organic/inorganic perovskites (HOIPs) via the chirality-induced spin selectivity (CISS) effect, paving a new way in spintronics. Despite the high spin-polarized current enhancement, the intrinsic oxidation tendency of iodide ions brings about severe problems in the stability and lifetime of electronic devices. Here, spin-dependent charge transport properties in lead-bromide perovskites hybrid with chiral R/S-methylbenzylammonium (MBA), that is, (R/S-MBA)PbBr 3 are explored. Distinct from layered 2D iodide perovskites (R/S-MBA) 2 PbI 4 which experience obvious crystal degradation along time, (R/S-MBA)PbBr 3 maintain good crystallinity even in the oxidative, humid, and high-temperature environment due to the lower Fermi level of bromide than iodide. Magnetic conductive atomic force microscopy displays a spin filtration efficiency as high as 90%, showing negligible decay after 1 month. This work expands the spin transport to chiral bromide perovskites with higher stability, and thus provides significant support for the practical application of HOIPs in spintronics.

In most cases, the current flows uniformly through the device in the HRS and is restricted to a local region with high conductance known as a conducting filament (CF) in the LRS. [3] Among them, a specific memory device is termed as conductivebridge RRAM (CBRAM), where the formation/rupture of metallic conductive filaments are dominated by cation migration and redox processes. [4] Meanwhile, volatile resistance switching behaviors are commonly observed in CBRAM as threshold switching (TS). Analogous to the nonvolatile electrochemical metallization mechanism in terms of materials and structures, [5] the electrical resistance of such a threshold switching memristor (TSM) could decrease by orders of magnitude when an electric field is applied due to the formation of CFs with active metal (such as Ag or Cu) atoms. [6] Differently, the resistance returns back spontaneously after the termination of the external bias, yielding a superior I-V nonlinearity and unique temporal conductance evolution dynamics. [7] Recent years, the threshold switching memristors based on active metals are also called "diffusive memristors" to emphasize the diffusion dynamics of the metal species. [8] To be more comprehensively, redox-diffusive threshold switching memristor (RDTSM) might be the best choice to demonstrate the overall switching behavior. [1a] RDTSM has gained significant attention due to its similar advantages to RRAM, such as the simple structure, great fabricability and integrability, and compatibility with conventional CMOS technology. More importantly, it has great potential in many vital applications, such as two-terminal selectors with high nonlinearity, [9] high-powerefficient synaptic or neuronal devices with novel functions. [8,10] A specific application requires a correspondingly proper device. Figure 1 displays the measurement schematic of the key parameters of RDTSM, including selectivity (or nonlinearity), compliance currents, switching voltages (including threshold voltages and hold voltages),TS mode (unidirectional and bidirectional, as shown in Figure 1a,b, respectively), switching slopes (Figure 1c), response time (including delay and relaxation, as shown in Figure 1d) and endurance, which are all up to the material composition and device structure. [11] Therefore, With the rapid development of information technique in the big-data era, there is an extremely urgent demand for new circuit building blocks, represented by resistive switching memristors with high speed, high-density integration, and power-efficiency, to overcome the limitations of electronic device scaling and thus achieve non-von-Neumann neuromorphic computing. Redox-diffusive threshold switching memristors, based on the volatile formation/rupture of metallic conductive filaments, are attracting great attention for many novel applications, ranging from selectors to synaptic and neuronal devices. Here, how to design a proper redox-diffusive threshold switching memristor is comprehensively introduced, with particular focus on the effect of the devic...

Negative capacitance effect in ferroelectric materials provides a solution to the energy dissipation problem induced by Boltzmann distribution of electrons in conventional electronics. Here, we discover that besides ferroelectrics, the antiferroelectrics based on Landau switches also have intrinsic negative capacitance effect. We report both the static and transient negative capacitance effect in antiferroelectric PbZrO3 films and reveal its possible physical origin. The capacitance of the capacitor of the PbZrO3 and paraelectric heterostructure is demonstrated to be larger than that of the isolated paraelectric capacitor at room temperature, indicating the existence of the static negative capacitance. The opposite variation trends of the voltage and charge transients in a circuit of the PbZrO3 capacitor in series with an external resistor demonstrate the existence of transient negative capacitance effect. Strikingly, four negative capacitance effects are observed in the antiferroelectric system during one cycle scan of voltage pulses, different from the ferroelectric counterpart with two negative capacitance effects. The polarization vector mapping, electric field and free energy analysis reveal the rich local regions of negative capacitance effect with the negative dP/dE and (δ2G)⁄(δD2), producing stronger negative capacitance effect. The observation of negative capacitance effect in antiferroelectric films significantly extends the range of its potential application and reduces the power dissipation further.

Large fluctuations of key parameters in cation-based resistive random access memory (RRAM), which originate from stochastic growth of metallic conductive filaments, always impose a significant barrier to the practical application of memory devices. Here, we propose an ordinary bilayer oxide structure of Ag/TaOx/TaOy/Pt (x < y) to address this issue and achieve the performance enhancement of memory cells. This memory device is inclined to form nano-cone-shaped filaments under external bias, and the tips of filaments provide an electric field concentration, achieving an effective control of filament growth. Compared with the single-layer device Ag/TaOx/Pt, the bilayer device manifests a larger ON/OFF ratio, much lower operation voltages and RESET currents, a higher response speed, and better uniformity. The insertion of the oxygen-rich layer also brings about the tunability of switching voltages and the elimination of the negative-SET phenomenon. Our experiments might pave the way for high-density emerging memory commercial applications.