Surface‐Energy‐Driven Growth of ZnO Hexagonal Microtube Optical Resonators
Surface‐Energy‐Driven Growth of ZnO Hexagonal Microtube Optical Resonators
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DOI：
10.1002/adom.201500442
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发表时间：
2016-01
影响因子：
9
通讯作者：
J. Zhan;Hongxing Dong;Shulin Sun;X. Ren;Jianjun Liu;Zhanghai Chen;C. Lienau;Long Zhang
中科院分区：
文献类型：
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作者：
J. Zhan;Hongxing Dong;Shulin Sun;X. Ren;Jianjun Liu;Zhanghai Chen;C. Lienau;Long Zhang
首次观察到管状氧化锌微/纳米结构具有明显的“裂解-复生”生长机制。在实验生长研究和第一性原理计算的基础上，提出了在传统的碳热还原工艺中加入H2/H2O蒸汽，改变了氧化锌晶体的本征表面能，从而影响了氧化锌晶体的生长模式，进而控制了氧化锌微纳米管的几何形状。结果表明，这些管状氧化锌微/纳米结构具有规则的六边形横截面和光滑的内外表面。对氧化锌微纳米管的光学研究揭示了其发射光谱的特征相干强度调制，这反映了回音廊模式或波导模的激发。可以通过控制微管的几何形状，特别是其壁厚与直径之比来选择特定类型的模式，如光致发光光谱实验和有限元模拟理论所证明的那样。
A distinct “split and recoalescence” growth mechanism of tubular ZnO micro/nanostructures is observed for the first time. On the basis of experimental growth studies and first‐principles calculations, it is proposed that H2/H2O vapor, added to the traditional carbothermal reduction process, changes the intrinsic surface energy of ZnO crystal, which affects the ZnO crystal growth mode and subsequently controls the geometry of ZnO micro/nanotubes. It is shown that these tubular ZnO micro/nanostructures exhibit regular hexagonal cross sections and smooth outer and inner surfaces. Optical studies of ZnO micro/nanotubes reveal characteristic coherent intensity modulations of their emission spectra which reflect the excitation of either whispering gallery modes or wave‐guided modes. The specific type of mode can be selected by controlling the microtube geometry, specifically by its wall thickness to diameter ratio, as demonstrated both experimentally by photoluminescence spectroscopy, and theoretically by finite‐element‐method simulations.