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Memristor based neuromorphic computing system has recently attracted enormous attention due to its fast and energy-efficient matrix vector multiplication, thus providing a novel approach to implement neural networks for artificial intelligence. However, the widely studied analogue memristors exhibit major flaws in terms of high conductance variation and nonlinear/asymmetric characteristics. In this work, we develop global gate controlled one transistor one digital memristor (1T1DM) architecture as the basic binary electronic synapse. Inspired by the current research highlights about low-bit networks, we further implement low-bit neuromorphic computing onto our 1T1DM systems by simulation. Compared to the classical analogue type of memristor with one transistor one analogue memristor (1T1R) structure, our 1T1DM network is light-weighted, highly robust and can work well on challenging visual tasks. Besides, benefiting from the global gated device structure, the on-state conductance of the digital memristors in the network can be simultaneously modulated by the controlling gate, offering possibility to tune the power consumption and operation speed while will not increase the circuit complexity.

Achieving low contact resistance is one of the main challenges for black phosphorus (BP) transistors for both electronic and optoelectronic applications. Here we demonstrate a novel yet feasible lithium doping technique, which greatly reduces the contact resistance from 2 to 0.85 $\text{k}\Omega \cdot \mu \text{m}$ and results in more than 2.5 times improvement in output current and ON/OFF ratio. This can be mainly attributed to the high hole doping density by lithium bis(trifluoromethylsulfonyl)-imide, which results in a narrower carrier injection barrier at the source end. The ON/OFF ratios of BP field-effect transistors with contact doping at 300 and 20 K are 432 and $7.2 \times 10^{5}$ , respectively. A high drain current of $773~\mu \text{A}/\mu \text{m}$ with a $0.56~\mu \text{m}$ channel length at 20 K is also demonstrated. The doping technique provides a valid way to improve the overall performance of BP transistors.

As an emerging two-dimensional material, few-layer black phosphorus (BP) shows great potential in nanoelectronics and nanophotonics due to its high carrier velocity. However, non-optimized gate dielectrics often degrade the performance of BP devices severely. In this letter, we demonstrate high-performance BP devices using a novel HfLaO as back gate dielectric with improved interface quality. High current exceeding 1.15 mA/ $\mu \text{m}$ has been achieved at 20 K for BP transistors with improved noise spectral density. Moreover, BP photodetectors with a record high photoresponsivity up to $1.5\times 10^{8}$ A/W and fast response time of $10~\mu \text{s}$ at 300 K are demonstrated. Excellent photoresponse in a broadband spectrum range from 514 to 1800 nm at 70 K has also been achieved.