The high activation energy required for graphite–diamond transition limits its applicability in novel areas. To exploit fully the multifunctional properties of diamond in diverse fields, there is a necessity to explore more efficient ways for its synthesis. In this study, we have demonstrated a new approach for nanodiamonds formation by employing a commercially available low power 10 W continuous-wave fibre laser. The laser system is modulated to generate the high-pressure high temperature environment necessary for the phase conversion of graphite to diamond. The microsecond pulse duration combined with liquid confinement effect on plasma provide scope for a lower rate of supercooling, which restricts the epitaxial growth of the crystals. The sample is characterized by X-ray powder diffraction, transmission electron microscope and Raman spectroscopy, confirming the presence of different types of nanodiamonds including newly discovered n-diamond. The process offers many important advantages like scalable process, non-catalyst-based eco-friendly and cost-effective synthesis of metastable nanodiamonds. The results demonstrate the effectuality of inexpensive commercial lasers towards attaining the localized extreme environment necessary for direct phase conversion of diamond materials.

中文翻译：

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使用 10 W 光纤激光器从石墨形成金刚石纳米结构

石墨-金刚石转变所需的高活化能限制了其在新领域的适用性。为了在不同领域充分利用金刚石的多功能特性，有必要探索更有效的合成方法。在这项研究中，我们通过使用市售的低功率 10 W 连续波光纤激光器展示了一种形成纳米金刚石的新方法。激光系统被调制以产生石墨到金刚石相转变所必需的高压高温环境。微秒脉冲持续时间与等离子体的液体限制效应相结合，为较低的过冷率提供了空间，这限制了晶体的外延生长。样品通过 X 射线粉末衍射表征，透射电子显微镜和拉曼光谱，确认存在不同类型的纳米金刚石，包括新发现的 n-金刚石。该工艺提供了许多重要的优势，例如可扩展的工艺、基于非催化剂的亚稳态纳米金刚石的生态友好和经济高效的合成。结果证明了廉价的商用激光器在实现金刚石材料直接相转换所需的局部极端环境方面的有效性。