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181.
Multi‐quantum well structures of 3C/4H‐SiC polytypes grown either on stepped or on on‐axis hexagonal SiC by molecular beam epitaxy have been investigated by conventional and high resolution TEM. The 3C‐SiC layers were nearly free of defects and the interface between different polytypes was abrupt. For the 3C‐SiC layers the strain state and the lattice parameters have been investigated to a high accuracy by convergent beam electron diffraction (CBED). 相似文献
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原子是物质世界中最基本的构成单元。原子制造通过精确操纵原子及功能基元来从最底层创造全新的物质、材料和器件,并构建具有革命性能的装备和系统。原子制造既是先进制造技术的极致化,也是量子理论的试验场,还是物质科学的未来技术,甚至未来态。文章以团簇束流、扫描隧道显微镜、原子级多层异质结以及其他单原子体系为例,介绍原子精准操控技术及其放大和集成,并探讨了原子制造在物质科学中的发展意义和未来前景。
相似文献186.
Reetendra Singh Dr. Uttam Gupta Dr. V. Sampath Kumar Mohd Monis Ayyub Prof. Umesh V. Waghmare Prof. C. N. R. Rao 《Chemphyschem》2019,20(13):1728-1737
Covalently cross-linked heterostructures of 2D materials are a new class of materials which possess electrochemical and photochemical hydrogen evolution properties. It was of considerable interest to investigate the role of interlayer spacing in the nanocomposites involving MoS2 and graphene sheets and its control over electronic structures and catalytic properties. We have investigated this problem with emphasis on the hydrogen evolution properties of these structures by a combined experimental and theoretical study. We have linked MoS2 based nanocomposites with other 2D materials with varying interlayer spacing by changing the linker and studied their hydrogen evolution properties. The hydrogen evolution activity for these composites decreases with increasing linker length, which we can link to a decrease in magnitude of charge transfer across the layers with increasing interlayer spacing. Factors such as the nature of the sheets, interlayer distance as well as the nature of the linker provide pathways to tune the properties of covalently cross-linked 2D material rendering this new class of materials highly interesting. 相似文献
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Dr. Xiaoshan Wang Yao Liu Jie Dai Qian Chen Prof. Xiao Huang Prof. Wei Huang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(17):3870-3876
The formation of semiconductor heterostructures is an effective approach to achieve high performance in electrical gas sensing. However, such heterostructures are usually prepared via multi-step procedures. In this contribution, by taking advantage of the crystal phase-dependent electronic property of SnSex based materials, we report a one-step colloid method for the preparation of SnSe(x%)/SnSe2(100−x%) p–n heterostructures, with x ≈30, 50, and 70. The obtained materials with solution processability were successfully fabricated into NO2 sensors. Among them, the SnSe(50 %)/SnSe2(50 %) based sensor with an active layer thickness of 2 μm exhibited the highest sensitivity to NO2 (30 % at 0.1 ppm) with a limit of detection (LOD) down to 69 ppb at room temperature (25 °C). This was mainly attributed to the formation of p–n junctions that allowed for gas-induced modification of the junction barriers. Under 405 nm laser illumination, the sensor performance was further enhanced, exhibiting a 3.5 times increased response toward 0.1 ppm NO2, along with a recovery time of 4.6 min. 相似文献
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Dr. Shikha Dhiman Dr. Akanksha Singh Prof. Subi J. George 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(2):705-711
Transient supramolecular self-assembly has evolved as a tool to create temporally programmable smart materials. Yet, so far single-component self-assembly has been mostly explored. In contrast, multicomponent self-assembly provides an opportunity to create unique nanostructures exhibiting complex functional outcomes, newer and different than individual components. Even two-component can result in multiple organizations, such as self-sorted domains or co-assembled heterostructures, can occur, thus making it highly complex to predict and reversibly modulate these microstructures. In this study, we attempted to create active bicomponent nanoparticle assemblies of orthogonally pH-responsive-group-functionalized gold and cadmium selenide nanoparticles with temporal microstructural control on their composition (self-sorted or co-assembly) in order to harvest their emergent transient photocatalytic activity by coupling to temporal changes in pH. Moving towards multicomponent systems can deliver next level control in terms of structural and functional outcomes of supramolecular systems. 相似文献
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Transition metal dichalcogenides (TMDCs) have suitable and adjustable band gaps, high carrier mobility and yield. Layered TMDCs have attracted great attention due to the structure diversity, stable existence in normal temperature environment and the band gap corresponding to wavelength between infrared and visible region. The ultra-thin, flat, almost defect-free surface, excellent mechanical flexibility and chemical stability provide convenient conditions for the construction of different types of TMDCs heterojunctions. The optoelectric properties of heterojunctions based on TMDCs materials are summarized in this review. Special electronic band structures of TMDCs heterojunctions lead to excellent optoelectric properties. The emitter, p-n diodes, photodetectors and photosensitive devices based on TMDCs heterojunction materials show excellent performance. These devices provide a prototype for the design and development of future high-performance optoelectric devices. 相似文献