Local Structure and Chemistry of C-Doped ZnO@C Core-Shell Nanostructures with Room-Temperature Ferromagnetism
Local Structure and Chemistry of C-Doped ZnO@C Core-Shell Nanostructures with Room-Temperature Ferromagnetism
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DOI：
10.1002/adfm.201704567
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发表时间：
2018-02-21
影响因子：
19
通讯作者：
Nguyen Duc Dung
中科院分区：
文献类型：
--
作者：
Duc-The Ngo;Le Thanh Cuong;Nguyen Duc Dung
提出了一种利用透射电子显微镜（TEM）定量研究C掺杂ZnO纳米结构精细结构的上级方法，首次揭示了碳在ZnO晶体中形成铁磁性的作用。TEM中的电子衍射显示纳米颗粒中的纤锌矿结构，其晶格参数（a = 0.327 +/- 0.03 nm和c = 0.529 +/- 0.04 nm）与原始结构略有不同。有趣的是，Zn-C键的键长为2.58埃的实验确定使用从电子衍射数据计算的原子对分布函数（PDF）。结合PDF中得到的C-C、Zn-O等键合，证明了C原子迁移到ZnO晶体中取代了O空位。这进一步通过高分辨率TEM成像和元素绘图可视化，并且强烈支持C掺杂的ZnO纳米颗粒中的铁磁性起源的提议，其中由C2 p-Zn 4s和O2 p-C2 p轨道形成的s-p和p-p杂化被认为引起铁磁性。
A superior approach is presented to study quantitatively fine structure of C-doped ZnO nanostructure using transmission electron microscopy (TEM) from which the role of carbon in ZnO crystal to form ferromagnetism is revealed at the first time. Electron diffraction in TEM shows Wurtzite structure in the nanoparticles with lattice parameters (a = 0.327 +/- 0.03 nm and c = 0.529 +/- 0.04 nm) slightly different from the original structure. Interestingly, the Zn-C bonding with a bonding length of 2.58 angstrom is experimentally determined using atomic pair distribution function (PDF) calculated from electron diffraction data. Together with other bondings, such as C-C, Zn-O obtained from the PDF, this demonstrates migration of C atoms into ZnO crystal to substitute O vacancies. This is furthermore visualized by high-resolution TEM imaging and elemental mapping, and strongly supports the proposal of origin of ferromagnetism in the C-doped ZnO nanoparticles where the s-p and p-p hybridizations formed by C2p-Zn4s, and O2p-C2p orbitals are believed to cause ferromagnetism.