Neuromorphic computing, which emulates the biological neural systems could overcome the high‐power consumption issue of conventional von‐Neumann computing. State‐of‐the‐art artificial synapses made of two‐terminal memristors, however, show variability in filament formation and limited capacity due to their inherent single presynaptic input design. Here, a memtransistor‐based artificial synapse is realized by integrating a memristor and selector transistor into a multiterminal device using monolayer polycrys‐talline‐MoS2 grown by a scalable chemical vapor deposition (CVD) process. Notably, the memtransistor offers both drain‐ and gate‐tunable nonvolatile memory functions, which efficiently emulates the long‐term potentiation/depression, spike‐amplitude, and spike‐timing‐dependent plasticity of biological synapses. Moreover, the gate tunability function that is not achievable in two‐terminal memristors, enables significant bipolar resistive states switching up to four orders‐of‐magnitude and high cycling endurance. First‐principles calculations reveal a new resistive switching mechanism driven by the diffusion of double sulfur vacancy perpendicular to the MoS2 grain boundary, leading to a conducting switching path without the need for a filament forming process. The seamless integration of multiterminal memtransistors may offer another degree‐of‐freedom to tune the synaptic plasticity by a third gate terminal for enabling complex neuromorphic learning.

Midinfrared (MIR), which covers numerous molecular vibrational fingerprints, has attracted enormous research interest due to its promising potential for label-free and damage-free sensing. Despite intense development efforts, the realization of waveguide-integrated on-chip sensing system has seen very limited success to date. The huge lattice mismatch between silicon and the commonly used detection materials such as HgCdTe, III–V, or II–VI compounds has been the key bottleneck that hinders their integration. Here, we realize an integration of silicon-on-insulator (SOI) waveguides with black phosphorus (BP) photodetectors. When operating near BP’s cutoff wavelength where absorption is weak, the light–BP interaction is enhanced by exploiting the optical confinement in the Si waveguide and grating structure to overcome the limitation of absorption length constrained by the BP thickness. Devices with different BP crystal orientation and thickness are compared in terms of their responsivity and noise equivalent power (NEP). Spectral photoresponse from 3.68 to 4.03 μm was investigated. Additionally, power-dependent responsivity and gate-tunable photocurrent were also studied. At a bias of 1 V, the BP photodetector achieved a responsivity of 23 A/W at 3.68 μm and 2 A/W at 4 μm and a NEP less than 1 nW/Hz1/2 at room temperature. The integration of passive Si photonics and active BP photodetector is envisaged to offer a potential pathway toward the realization of integrated on-chip systems for MIR sensing applications.

and intelligent applications including personalized feedback therapy, fast speech, and visual recognition. [1][2][3][4][5] In particular in the non-conventional space of smart applications requiring conformal attachment on non-flat surfaces such as on-body wearables, the notion of system on plastics (SOP) incorporating neuromorphic computing provides a potential solution. [1,2] To build such a flexible neuromorphic system, the fabrication of memristors equipped with synaptic functions is a key step to forming the artificial neural network. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] However, current memristor manufacturing technologies such as chemical vapor deposition (CVD), [7,8,[11][12][13] spin-coating, [14,15] or entire transfer [16] impose enormous challenges on flexible substrates as they suffer from high temperature, low yield and complex sacrificial layer removal. Efforts in finding low temperature fabrication technique and robust resistive switching (RS) material are essential to equip the SOP with the data storage and processing capability demanded by target applications. The printing technique-a forefront 3D monolithic integration approach-is suitable for high-volume, low-temperature manufacturing on non-conformal surfaces. [22][23][24][25][26][27][28] The printing technique is shown to offer more freedom in the design of Realization of memristors capable of storing and processing data on flexible substrates is a key enabling technology toward "system-on-plastics". Recent advancements in printing techniques show enormous potential to overcome the major challenges of the current manufacturing processes that require high temperature and planar topography, which may radically change the system integration approach on flexible substrates. However, fully printed memristors are yet to be successfully demonstrated due to the lack of a robust printable switching medium and a reliable printing process. An aerosol-jet-printed Ag/MoS 2 /Ag memristor is realized in a cross-bar structure by developing a scalable and low temperature printing technique utilizing a functional molybdenum disulfide (MoS 2 ) ink platform. The fully printed devices exhibit an ultra-low switching voltage (0.18 V), a high switching ratio (10 7 ), a wide range of tuneable resistance states (10-10 10 Ω) for multi-bit data storage, and a low standby power consumption of 1 fW and a switching energy of 4.5 fJ per transition set. Moreover, the MoS 2 memristor exhibits both volatile and non-volatile resistive switching behavior by controlling the current compliance levels, which efficiently mimic the short-term and longterm plasticity of biological synapses, demonstrating its potential to enable energy-efficient artificial neuromorphic computing.

We present a method for substitutional p-type doping in monolayer (1L) and few-layer (FL) WS using highly reactive nitrogen atoms. We demonstrate that the nitrogen-induced lattice distortion in atomically thin WS is negligible due to its low kinetic energy. The electrical characteristics of 1L/FL WS field-effect transistors (FETs) clearly show an n-channel to p-channel conversion with nitrogen incorporation. We investigate the defect formation energy and the origin of p-type conduction using first-principles calculations. We reveal that a defect state appears near the Fermi level, leading to a shallow acceptor level at 0.24 eV above the valence band maximum in nitrogen-doped 1L/FL WS. This doping strategy enables a substitutional p-type doping in intrinsically n-type 1L/FL transition metal dichalcogenides (TMDCs) with tunable control of dopants, offering a method for realizing complementary metal-oxide-semiconductor FETs and optoelectronic devices on 1L/FL TMDCs by overcoming one of the major limits of TMDCs, that is, their n-type unipolar conduction.

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