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Novel SiOC nanocomposites were successfully synthesized from commercial silica sol and sucrose via a simply designed route. The formation of SiOC nanocomposites was studied using thermogravimetry and differential scanning calorimetry. The synthesized nanocomposites were characterized by Fourier transform infrared spectroscopy, x-ray fluorescence spectrometer, x-ray photoelectron spectroscopy, x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results indicate that the synthesized composites are amorphous in nature and homogeneous with the microstructure of close packed SiO(2) and carbon at nanoscale. The SiOC nanocomposites exhibit very high reactivity and can be annealed to produce SiC nanocrystals at 1200 degrees C which is about 300 degrees C lower than the value obtained by thermodynamic calculation. Ultra-large-scale beta-SiC nanowires with high quality were prepared by directly annealing the synthesized SiOC nanocomposites at 1500 degrees C under Ar atmosphere, where the yield of SiC nanowires was up to 59%. The SiC nanowires grow along the [111] direction with highly uniform diameters of about 100 nm. Experimental results indicate that the close contact between SiO(2) and carbon at nanoscale plays a vital role in the high yield of SiC nanowires. The present work provides an efficient strategy for the large scale production of high-quality SiC nanowires.

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Near-infrared (NIR) synaptic devices integrate NIR optical sensitivity and synaptic plasticity, emulating the basic biomimetic function of the human visual system and showing great potential in NIR artificial vision systems. However, the lack of semiconductor materials with appropriate band gaps for NIR photodetection and effective strategies for fabricating devices with synaptic behaviors limit the further development of NIR synaptic devices. Here, a two-terminal NIR synaptic device consisting of the In2Se3/MoS2 heterojunction has been constructed, and it exhibits fundamental synaptic functions. The reduced band gap and potential barrier of In2Se3/MoS2 heterojunctions are essential for NIR synaptic plasticity. In addition, the NIR synaptic properties of In2Se3/MoS2 heterojunctions under strain have been studied systematically. The ΔEPSC of the In2Se3/MoS2 synaptic device can be improved from 38.4% under no strain to 49.0% under a 0.54% strain with a 1060 nm illumination for 1 s at 100 mV. Furthermore, the artificial NIR vision system consisting of a 10 × 10 In2Se3/MoS2 device array has been fabricated, exhibiting image sensing, learning, and storage functions under NIR illumination. This research provides new ideas for the design of flexible NIR synaptic devices based on 2D materials and presents many opportunities in artificial intelligence and NIR vision systems.

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