材料科学
晶格常数
十二面体
结晶学
衍射
拉曼光谱
面(心理学)
透射电子显微镜
表层
凝聚态物理
电子衍射
格子(音乐)
分子物理学
光学
纳米技术
图层(电子)
化学
心理学
社会心理学
物理
人格
声学
五大性格特征
作者
Bo‐Hao Chen,Gautam Kumar,Yu‐Jung Wei,Hsueh‐Heng Ma,Jui‐Cheng Kao,Po‐Jung Chou,Yu‐Chun Chuang,I‐Chia Chen,Jyh‐Pin Chou,Yu‐Chieh Lo,Michael H. Huang
出处
期刊:Small
[Wiley]
日期:2023-06-28
卷期号:19 (44)
被引量:10
标识
DOI:10.1002/smll.202303491
摘要
Semiconductor crystals have generally shown facet-dependent electrical, photocatalytic, and optical properties. These phenomena have been proposed to result from the presence of a surface layer with bond-level deviations. To provide experimental evidence of this structural feature, synchrotron X-ray sources are used to obtain X-ray diffraction (XRD) patterns of polyhedral cuprous oxide crystals. Cu2 O rhombic dodecahedra display two distinct cell constants from peak splitting. Peak disappearance during slow Cu2 O reduction to Cu with ammonia borane differentiates bulk and surface layer lattices. Cubes and octahedra also show two peak components, while diffraction peaks of cuboctahedra are comprised of three components. Temperature-varying lattice changes in the bulk and surface regions also show shape dependence. From transmission electron microscopy (TEM) images, slight plane spacing deviations in surface and inner crystal regions are measured. Image processing provides visualization of the surface layer with depths of about 1.5-4 nm giving dashed lattice points instead of dots from atomic position deviations. Close TEM examination reveals considerable variation in lattice spot size and shape for different particle morphologies, explaining why facet-dependent properties are emerged. Raman spectrum reflects the large bulk and surface lattice difference in rhombic dodecahedra. Surface lattice difference can change the particle bandgap.
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