EAGER: Low-Temperature Plasmas for Synthesis of Diamond Nanoparticles

虽然钻石被视为宝石，但很少有人意识到钻石为光电器件提供的巨大技术潜力。金刚石是一种宽带隙半导体，具有极高的导热性，使其成为一系列应用的首选材料，包括量子计算，植入式生物医学设备和高压电子设备-超出工业金刚石传统切割钻头用途的应用。当金刚石以纳米颗粒的形式制成时，由于尺寸引起的性质变化以及将纳米颗粒引入薄膜应用的容易性，其性能增加。挑战在于，以可扩展的方式合成高质量的金刚石纳米颗粒是困难的，并且在如何产生金刚石纳米颗粒方面存在许多科学知识空白。碳-碳键可以形成石墨或金刚石，控制反应过程中产生的键仍然是一个悬而未决的问题。该研究计划旨在扩展令人兴奋的早期结果，这些结果表明金刚石纳米颗粒可以在低温等离子体（LTP）反应器中形成，这种方法有望对如何以高质量和高产量生产金刚石产生新的理解。这项研究的预期结果是发现新的反应途径，以控制金刚石生长的流通LTP的能力，选择键形成过程中的反应。如果成功，这项工作将能够为各种关键应用创造金刚石纳米颗粒，并为其他半导体纳米材料的LTP中的键形成产生新的知识。拟议的研究还将与推广活动结合使用，以鼓励在工程中代表性不足的群体的参与。低温等离子体（LTP）合成纳米粒子已经获得了越来越多的关注，因为这些反应器能够以可扩展的方式生产高质量和可调性能的纳米粒子。LTP合成纳米颗粒的根本挑战是关于反应器参数如何直接影响纳米颗粒生长的知识缺口。这一挑战在碳系统的背景下被放大，碳系统的特点是sp2和sp3杂化，导致显着不同的碳基材料-即石墨烯/石墨和金刚石。在这项工作中，有前途的初步结果的基础上，选择性键杂化在射频和微波LTP反应器通过控制等离子体和反应器参数将被研究用于合成金刚石纳米颗粒。专注于纳米颗粒的合成允许由于尺寸依赖性而增加的功能可调性。LTP反应器的独特之处在于，它们提供对各种光刻性能的控制，包括尺寸、表面功能和掺杂，以及使用惯性冲击、扩散或甚至直接写入沉积成图案的受控沉积。这项研究将产生反应器操作参数和所得纳米颗粒性质之间的映射，包括发现反应期间选择键杂化所需的条件。拟议的工作将建立一个基本的图片如何金刚石成核和生长发生，填补了关键的差距，了解确切的能量和生长条件要求的金刚石合成，相比石墨合成，在LTP reactors.This奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

While diamonds are prized as gemstones, few realize the immense technological potential that diamond offers for optoelectronic devices. Diamond is a wide-bandgap semiconductor with extraordinarily high thermal conductivity, making it a material of choice for a range of applications including quantum computing, implantable biomedical devices, and high-voltage electronics – applications beyond the traditional cutting bit uses of industrial diamonds. When diamond is made in nanoparticle form, its capabilities increase because of size-induced changes to properties and the ease of incorporating nanoparticles into thin film applications. The challenge is that synthesizing diamond nanoparticles with high quality and in a scalable manner is difficult, and there are many scientific knowledge gaps on how diamond nanoparticles are created. Carbon-carbon bonds can form either graphite or diamond, and control over which bond is generated in reactive processes remains an open problem. This research plan intends to expand on exciting early results indicating that diamond nanoparticles can be formed in low-temperature plasma (LTP) reactors, in an approach that promises new understanding of how diamond can be generated with high quality and high yield. The expected results of this research are the discovery of new reaction pathways to control diamond growth in flow-through LTPs with the capability to select bond formation during the reaction. If successful, this work will enable the creation of diamond nanoparticles for a variety of critical applications, as well as generate new knowledge around bond formation in LTPs for other semiconductor nanomaterials. The proposed research will also be used in conjunction with outreach events to encourage participation of underrepresented groups in engineering.Low-temperature plasma (LTP) synthesis of nanoparticles has gained growing attention for the ability of these reactors to produce high-quality and tunable-property nanoparticles in a scalable manner. The fundamental challenge in LTP synthesis of nanoparticles is a gap in knowledge about how reactor parameters directly influence nanoparticle growth. This challenge is amplified in the context of the carbon system, which features both sp2 and sp3 hybridization that result in dramatically different carbon-based materials – namely, graphene/graphite and diamond. In this work, based on promising preliminary results, selective bond hybridization in radiofrequency and microwave LTP reactors via control over plasma and reactor parameters will be investigated for synthesis of diamond nanoparticles. Focusing on synthesis of nanoparticles allows for added functional tunability because of size-dependent properties. LTP reactors are unique in that they offer control over a variety of nanocrystal properties, including size, surface functionality, and doping together with controlled deposition using inertial impaction, diffusion, or even direct-write deposition into patterns. This research will produce a map between reactor operating parameters and resulting nanoparticle properties, including discovering the conditions that are required for selected bond hybridization during the reaction. The proposed work will build a fundamental picture of how nanocrystal nucleation and growth occur, filling a critical gap in understanding about the exact energetic and growth condition requirements for diamond synthesis, as compared to graphite synthesis, in LTP reactors.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.