Direct Conversion of Carbon into Diamond and Useful Micro and Nanostructures

非技术描述：该项目的重点是在环境温度和大气压力下将碳直接转化为钻石。通过NCSU的变革性方法，碳可以在各种有用的纳米结构和微观结构中转化为所谓的q -碳（因激光淬火而命名）和金刚石，以纳米针、微针、纳米点、微晶体和大面积单晶薄膜的形式出现在蓝宝石、玻璃和热敏聚合物等实用衬底上。这些微尺度和纳米尺度的结构具有潜在的应用，例如，作为切削工具和高速加工；在高功率、量子计算设备和生物医学设备中。在这个非常关键的阶段，目标是发展一个基本的理解和解决与扩大和制造钻石相关产品有关的问题。该项目通过与北卡罗来纳理工学院的师生合作，在这个令人兴奋的新领域培养研究生，具有很强的教育价值。技术细节：这项研究解决了对碳直接转化为钻石的基本机制的基本理解和调查。利用纳秒脉冲激光照射，碳在4000 K（比碳熔点低1000 K以上）下处于高度过冷状态熔化。然后，这种状态被淬火形成q -碳（碳的一种新相）或金刚石或两者的混合物；结果取决于过冷的程度。q -碳具有许多令人兴奋的新特性，包括铁磁性，超硬度和增强的场发射，可用于下一代显示器。q -碳通过第二脉冲激光照射转化为金刚石。通过控制纳米点在快速淬火过程中的界面不稳定性，利用单纳秒激光脉冲形成微点、纳米针和微针；整个过程在不到200纳秒的时间内完成。这种新颖的方法提供了一种廉价的方法将碳转化为金刚石，并方便地收获各种结构，用于各种应用。本研究扩展了我们在激光-固体相互作用和材料瞬态热加工方面的基础知识，以及结构、缺陷和化学在新型q -碳和金刚石基结构性能中的关键作用。

NON-TECHNICAL DESCRIPTION: This project focuses on direct conversion of carbon into diamond at ambient temperatures and atmospheric pressures in air. By NCSU's transformative approach, carbon can be converted into so-called Q-carbon (named because of laser quenching) and diamond in a variety of useful nanostructures and microstructures in the form of nanoscale needles, microscale needles, nanoscale dots, microscale crystals, and large-area single-crystal films on practical substrates such as sapphire, glass and heat-sensitive polymers. These microscale and nanoscale structures have potential applications, e.g., as cutting tools and high-speed machining; and in high-power, quantum computing devices, and biomedical devices. The goals in this very critical stage are to develop a basic understanding and address issues related to scale-up and manufacturing of diamond-related products. This project has a strong education value through training of graduate students in this exciting new area in collaboration with NC A&T faculty and students.TECHNICAL DETAILS: This research addresses fundamental understanding and investigations of basic mechanisms involved in the direct conversion of carbon into diamond. By using nanosecond pulsed laser irradiation, carbon is melted in a highly undercooled state at 4000 K (over 1000 K below the melting point of carbon). This state is then quenched to form Q-carbon (a new phase of carbon) or diamond or a mixture of both; the result depends on the degree of undercooling. Q-carbon has many exciting new properties, including ferromagnetism, super hardness and enhanced field emission for next-generation displays. Q-carbon is converted into diamond by laser irradiation with a second laser pulse. By controlling interfacial instability during rapid quenching nanodots, microdots, nanoneedles and microneedles are created with a single nanosecond laser pulse; the entire process is completed in less than two hundred nanoseconds. This novel approach provides an inexpensive way to convert carbon into diamond and harvest various structures conveniently for a variety of applications. This research expands our fundamental knowledge base on laser-solid interactions and transient thermal processing of materials, and on the critical role of structure, defects and chemistry in the properties of novel Q-carbon and diamond-based structures.