Synthesis and carbothermal nitridation mechanism of ultra-long single crystal alpha-Si3N4 nanobelts
Synthesis and carbothermal nitridation mechanism of ultra-long single crystal alpha-Si3N4 nanobelts
复制标题
超长单晶α-Si3N4纳米带的合成及碳热氮化机理
DOI：
10.1088/1361-6528/ab6fd7
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发表时间：
2020
期刊：
影响因子：
3.5
通讯作者：
Ishizaki Kozo
中科院分区：
文献类型：
--
作者：
Wang Bo;Huang Xin;Zhou Xiao-Nan;Zhi Qiang;Hao Liu-Cheng;Li Zi-Xuan;Zhao Shan;Hou Bao-Qiang;Yang Jian-Feng;Ishizaki Kozo
一维Si 3 N4纳米结构由于其独特的形貌而被广泛应用于电子和光电子器件的制备。本文提出了一种简便、无催化剂的方法，在1750 °C下通过碳纳米管的碳热氮化合成超长单晶α-Si 3 N4纳米带。得到的α-Si 3 N4纳米带具有平坦的表面（厚度约150 nm，长度为几毫米），显示出极高的纵横比，完美的晶体结构，以及7.34-10.09 m2 g-1的高比表面积。此外，通过将保温时间从1 h增加到3 h，可将宽度从约80 nm增加到8 μm。纳米带的形成受SiO蒸气、N2和碳纳米管之间的气-固（VS）反应以及SiO、CO和N2之间的气-气反应控制。前者负责α-Si_3N_4纳米管的初始形核和随后的基底生长。后者还有助于纳米棒和随后的原始纳米带的形成和纳米带的生长。在1750 °C的高温退火过程中，原始的Si 3 N4纳米管逐渐转变为纳米棒，最终由于表面能最小化而形成具有稳定形状的纳米带。
One-dimensional Si3N4 nanostructures are desirable for constructing nanoscale electric and optoelectronic devices due to their peculiar morphologies. Herein, a facile and environmentally friendly catalyst-free method is proposed to synthesize ultra-long single crystal α-Si3N4 nanobelts via carbothermal nitridation of carbon nanotubes at 1750 °C. The obtained α-Si3N4 nanobelts with a flat surface (thickness of ∼150 nm, length of several millimeters) exhibited an extremely high aspect ratio, perfect crystal structure, and high specific surface area of 7.34–10.09 m2 g−1. In addition, the width was increased from approximately 80 nm to 8 μm by increasing the holding time from 1 to 3 h. The nanobelt formation was governed by the vapor–solid (VS) reaction between SiO vapor, N2 and carbon nanotubes, and the vapor–vapor reaction between SiO, CO and N2. The former was responsible for the initial nucleation and successive base-growth of α-Si3N4 nanotubes. The latter additionally contributed to the nanorod and subsequent proto-nanobelt formation and to the growth of the nanobelts. During high-temperature annealing at 1750 °C, the original Si3N4 nanotubes gradually transformed into nanorods, and, finally, nanobelts with stable shapes as a result of surface energy minimization.