Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Nat Nanotechnol. 2013 May;8(5):347-55. doi: 10.1038/nnano.2013.56. Epub 2013 Apr 28.
Among the remarkable variety of semiconducting nanomaterials that have been discovered over the past two decades, single-walled carbon nanotubes remain uniquely well suited for applications in high-performance electronics, sensors and other technologies. The most advanced opportunities demand the ability to form perfectly aligned, horizontal arrays of purely semiconducting, chemically pristine carbon nanotubes. Here, we present strategies that offer this capability. Nanoscale thermocapillary flows in thin-film organic coatings followed by reactive ion etching serve as highly efficient means for selectively removing metallic carbon nanotubes from electronically heterogeneous aligned arrays grown on quartz substrates. The low temperatures and unusual physics associated with this process enable robust, scalable operation, with clear potential for practical use. We carry out detailed experimental and theoretical studies to reveal all of the essential attributes of the underlying thermophysical phenomena. We demonstrate use of the purified arrays in transistors that achieve mobilities exceeding 1,000 cm(2) V(-1) s(-1) and on/off switching ratios of ∼10,000 with current outputs in the milliamp range. Simple logic gates built using such devices represent the first steps toward integration into more complex circuits.
在过去二十年中发现的各种半导体纳米材料中，单壁碳纳米管仍然是最适合用于高性能电子、传感器和其他技术的材料。最先进的应用机会需要能够形成完美排列的、水平的纯半导体、化学纯净的碳纳米管阵列。在这里，我们提出了实现这一能力的策略。薄膜有机涂层中的纳米尺度热毛细流，随后进行反应离子刻蚀，是从在石英衬底上生长的电子异质排列的阵列中选择性去除金属碳纳米管的高效手段。与该工艺相关的低温和异常物理现象使其能够实现稳健、可扩展的操作，具有实际应用的巨大潜力。我们进行了详细的实验和理论研究，揭示了基础热物理现象的所有基本属性。我们展示了在晶体管中使用纯化后的碳纳米管阵列，这些晶体管的迁移率超过 1000cm^2/V/s，开关比约为 10000，电流输出在毫安范围内。使用此类器件构建的简单逻辑门代表了集成到更复杂电路的第一步。
