The isolation of black phosphorus (BP) and extraordinary performance of the BP field-effect transistor have led to BP offering remarkable properties in the two-dimensional (2D) family. Along with BP, other group VA element materials have been demonstrated to possess superior electronic and optical properties. However, numerous challenges remain to be overcome in their practical applications. Heterostructures play a vital role in modern semiconductors, and 2D group VA materials provide the opportunity to fabricate novel heterostructures that are combined by van der Waals forces. Previous theoretical and experimental studies have indicated that constructing a heterostructure is a promising strategy to conquer the obstacles and boost the development of 2D group VA materials. In this paper, we summarize the recent progress in 2D group VA material-based heterostructures. Firstly, the crystal structures and fundamental electrical properties of 2D group VA materials are introduced. Thereafter, various heterostructures based on group VA materials are discussed. Finally, conclusions and the outlook on emerging group VA heterostructures are presented.

Neuromorphic computing, which mimics brain function, can address the shortcomings of the "von Neumann" system and is one of the critical components of next-generation computing. The use of light to stimulate artificial synapses has the advantages of low power consumption, low latency, and high stability. We demonstrate amorphous InAlZnO-based light-stimulated artificial synaptic devices with a thin-film transistor structure. The devices exhibit fundamental synaptic properties, including excitatory postsynaptic current, paired-pulse facilitation (PPF), and short-term plasticity to long-term plasticity conversion under light stimulation. The PPF index stimulated by 375 nm light is 155.9% when the time interval is 0.1 s. The energy consumption of each synaptic event is 2.3 pJ, much lower than that of ordinary MOS devices and other optical-controlled synaptic devices. The relaxation time constant reaches 277 s after only 10 light spikes, which shows the great synaptic plasticity of the device. In addition, we simulated the learning-forgetting-relearning-forgetting behavior and learning efficiency of human beings under different moods by changing the gate voltage. This work is expected to promote the development of high-performance optoelectronic synaptic devices for neuromorphic computing.

Electrocatalysts play a key role in accelerating the sluggish electrochemical CO2 reduction (ECR) involving multi-electron and proton transfer. Herein, we develop a proton capture strategy via accelerating the water dissociation reaction catalyzed by transition metal nanoparticles (NPs) adjacent to atomically dispersed Ni-Nx active sites (Ni@NiNCM) to accelerate the proton transfer to the latter for boosting the intermediate protonation step, and hence the whole ECR process. For the first time, the accelerated protonation process is amply demonstrated experimentally. Aberration-corrected scanning transmission electron microscopy and synchrotron radiation X-ray absorption spectroscopy, together with DFT calculations, revealed that the Ni NPs accelerated the adsorbed H (Had) generation and transfer to the adjacent Ni-Nx sites for boosting the intermediate protonation and the overall ECR processes. This proton capture strategy is highly general, which can be extended to the design and preparation of various high-performance catalysts for diverse electrochemical reactions even beyond ECR.

Heterojunctions of Ta 2 O 5 and multiwalled carbon nanotubes (MWCNTs) have been successfully synthesized by a facile and cost-effective hydrothermal method, with a super thin and uniform Ta 2 O 5 shell wrapped around the MWCNT. The combination of Ta 2 O 5 and MWCNTs at the interface not only modifies the morphology but also forms the p−n heterojunction, which contributes to the reconstruction of band structure, as well as the low resistance of matrix and highly chemisorbed oxygen content. The Ta 2 O 5 @MWCNT p−n heterojunction exhibits ultrasensitive performance to ethanol at room temperature, with a response of 3.15 toward 0.8 ppm ethanol and a detection limit of 0.173 ppm. The sensor has a high reproducibility at various concentrations of ethanol, superior selectivity to other gases, and long-term stability. The strategy of hybriding metal oxide semiconductors with MWCNT promises to provide a feasible and further developable pathway for high-performance room-temperature gas sensors.