Abstract

The interior of spontaneously growing graphitized microstructures formed in diamond bulk by picosecond laser pulses has been studied. Longitudinal and cross sections of microstructures, prepared using mechanical polishing and focused ion beam, have been studied by Raman spectroscopy and scanning electron–ion microscopy. The laser irradiation of diamond bulk is found to induce formation of a graphite nanonetwork in the processed region and its subsequent spontaneous growth towards the laser beam by a distance of ~60 µm. The graphite nanonetwork consists of many ~130-nm-thick graphite sheets clustered into segments. It is shown that the thickness of graphite sheets decreases with a decrease in the laser fluence at the modification front, whereas the segment length (~2.6 µm) is independent of the laser fluence at the modification front. A three-dimensional structural model of microsegment has been constructed based on the analysis of several longitudinal and cross sections of microstructures. The mechanism of graphite nanosheet clustering into microsegments is discussed.

中文翻译：

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金刚石中激光诱导石墨纳米网络的空间自组织

摘要

研究了通过皮秒激光脉冲在金刚石块中自发生长的石墨化微结构的内部。通过机械抛光和聚焦离子束制备的微观结构的纵向和横截面，已通过拉曼光谱和扫描电子离子显微镜进行了研究。发现金刚石散装物的激光辐照会在加工区域中诱导形成石墨纳米网络，并随后朝着激光束自发生长约60 µm的距离。石墨纳米网络由许多〜130-nm厚的石墨片聚集成段组成。结果表明，石墨片的厚度随着改性前沿的激光通量的减小而减小，而段长（〜2.6 µm）与改性前沿的激光通量无关。基于对微结构的若干纵向和横截面的分析，已经构建了微分段的三维结构模型。讨论了石墨纳米片团聚成微段的机理。