Abstract Carbon nanotubes were developed via floating catalyst technique using acetylene and ferrocene as carbon and catalyst precursors respectively at temperatures varying from 700 to 1150 °C. Structure and morphology were characterized via SEM, TEM and Raman spectroscopy. The dimensions and yield of grown CNT's were observed to be same in all temperatures. The crystalline perfection of CNT's was improved with an increase in temperature. It is observed that the temperature of the synthesis could affect the degree of nanotubes graphitization. Catalytic growth of CNT's was elucidated on the basis of the model of vapour-liquid-solid and the proposed model was supported by TEM. Growth rate of nanotubes rises at higher temperatures and graphite sheets builds with lower defect. Nonlinear optical and limiting characteristics were determined using ns pulses at 532 nm. CNT's display strong nonlinear absorption coefficient of 29.9 cm/GW. CNT's exhibiting excellent optical limiting with a limiting threshold of 3 J/cm 2.

中文翻译：

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浮动催化剂技术开发的碳纳米管三阶非线性光学研究

摘要 碳纳米管是通过浮动催化剂技术开发的，分别使用乙炔和二茂铁作为碳和催化剂前体，在 700 到 1150 °C 的温度范围内变化。通过SEM、TEM和拉曼光谱表征结构和形态。观察到生长的 CNT 的尺寸和产量在所有温度下都相同。随着温度的升高，CNT的结晶完美度得到改善。据观察，合成温度会影响纳米管的石墨化程度。在汽-液-固模型的基础上阐明了碳纳米管的催化生长，所提出的模型得到了透射电镜的支持。纳米管的生长速度在更高的温度下上升，并且石墨片以更低的缺陷构建。非线性光学和限制特性是使用 532 nm 的 ns 脉冲确定的。CNT 显示出 29.9 cm/GW 的强非线性吸收系数。CNT 表现出出色的光学限制，限制阈值为 3 J/cm 2。