NER: Chemical Vapor Deposition of Carbon Nanotube/Diamond Composites

NER：碳纳米管/金刚石复合材料的化学气相沉积

• 批准号: 0304132
• 负责人: Nick Glumac
• 金额: $ 9.96万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2004-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0304132&HistoricalAwards=false
• 关键词: NER; Chemical; Vapor; Deposition; Carbon

PROJECT SUMMARY The objectives of this nanoscale exploratory research project are the growth of composite films of carbon nanotubes and diamond using chemical-vapor deposition, to extensively characterize these films, and to understand the film-growth process at the atomistic level through detailed simulations of the molecular processes. Carbon nanotubes (CNT) and diamond have properties that are individually exceptional but also complementary in a fashion such that a composite material made of these components should have truly unique properties. CNT are predicted to have extremely high values of Young's modulus while also being able to sustain large strain in the axial direction. It has been demonstrated that, using the tip of an AFM, multiwalled CNT can be bent repeatedly through large angles without causing any apparent fracture. On the other hand, diamond is the hardest known material and has the highest room-temperature thermal conductivity. Other properties include a very low coefficient of friction, good resistivity and optical transparency, and some superior semiconducting properties when appropriately doped. Recent research has shown that polycrystalline diamond can be readily deposited as a film on various substrates. Such diamond films have found applications primarily as wear-resistant coatings and heat-spreading devices, though film brittleness significantly limits the use of pure diamond films. In order to capitalize on the favorable properties of diamond while addressing the brittleness problem, a CNT/diamond composite material is manufactured that should have extreme hardness combined with outstanding toughness. The synthesis method is chemical vapor deposition (CVD) which is currently used to deposit both diamond and CNT under similar conditions. By careful selection of process conditions, a dense CNT/diamond film with a strong interface is produced that can be controlled and optimized by variation of reactor parameters. Deposition experiments are conducted in an existing CVD reactor, which is slightly modified to allow for CNT and diamond deposition on the same wafer. After the initial CNT film is generated, diamond is deposited using hot-filament CVD (HF-CVD). The structural properties of the composite films are characterized by high-resolution transmission electron microscopy. The roles of the substrate and catalyst on the growth of CNT and diamond, and the interface and internal film stresses are investigated. The mechanical properties of the composite are studied with atomic-force microscopy using a diamond-tipped probe. A complementary modeling and simulation effort provides understanding of the fundamental phenomena offers insight into remedial measures and potential process improvement.Broader impactThis work provides education and experience for university students in nanotechnology. Results obtained in this study are widely disseminated through conferences and archival journal publications. Should this effort at film synthesis be successful, a great potential for technology transfer with the emerging nanotechnology industry will be present. The involvement of students from under-represented groups is promoted through recruiting efforts, as well as through the university's formal SURGE program. Facility upgrades required for this project improve the infrastructure and enhance the ability to conduct research in the area of nanomaterials .

项目摘要 这个纳米级探索性研究项目的目标是使用化学气相沉积法生长碳纳米管和金刚石复合薄膜，广泛表征这些薄膜，并通过详细模拟了解原子水平上的薄膜生长过程。分子过程。 碳纳米管 (CNT) 和金刚石具有各自独特的特性，但又以某种方式互补，使得由这些成分制成的复合材料应具有真正独特的特性。 CNT 预计具有极高的杨氏模量值，同时还能够承受轴向的大应变。 已经证明，使用 AFM 尖端，多壁碳纳米管可以大角度反复弯曲，而不会造成任何明显的断裂。 另一方面，金刚石是已知最硬的材料，并且具有最高的室温导热率。其他特性包括非常低的摩擦系数、良好的电阻率和光学透明度，以及适当掺杂时的一些优异的半导体特性。 最近的研究表明，多晶金刚石可以很容易地在各种基材上沉积成薄膜。 这种金刚石薄膜主要用作耐磨涂层和散热装置，尽管薄膜的脆性极大地限制了纯金刚石薄膜的使用。 为了利用金刚石的有利特性，同时解决脆性问题，我们制造了一种碳纳米管/金刚石复合材料，该材料应具有极高的硬度和出色的韧性。合成方法是化学气相沉积（CVD），目前用于在类似条件下沉积金刚石和碳纳米管。通过仔细选择工艺条件，可以生产出具有强界面的致密碳纳米管/金刚石薄膜，并且可以通过改变反应器参数来控制和优化该薄膜。 沉积实验是在现有的 CVD 反应器中进行的，该反应器稍作修改以允许在同一晶圆上沉积 CNT 和金刚石。 生成初始 CNT 薄膜后，使用热丝 CVD (HF-CVD) 沉积金刚石。 复合膜的结构性能通过高分辨率透射电子显微镜进行表征。 研究了基底和催化剂对碳纳米管和金刚石生长的作用，以及界面和内部薄膜应力。 使用金刚石尖端探针通过原子力显微镜研究了复合材料的机械性能。 互补的建模和模拟工作提供了对基本现象的理解，提供了对补救措施和潜在过程改进的洞察。更广泛的影响这项工作为大学生提供了纳米技术方面的教育和经验。 这项研究获得的结果通过会议和档案期刊出版物广泛传播。 如果薄膜合成方面的努力取得成功，新兴纳米技术产业的技术转让将具有巨大潜力。 通过招募工作以及大学的正式 SURGE 计划，促进来自代表性不足群体的学生的参与。该项目所需的设施升级改善了基础设施并增强了在纳米材料领域进行研究的能力。