Ouyang M, Huang J L, Cheung C L, Lieber C M
Department of Chemistry and Chemical Biology and, Division of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA.
Science. 2001 Jan 5;291(5501):97-100. doi: 10.1126/science.291.5501.97.
Intramolecular junctions in single-walled carbon nanotubes are potentially ideal structures for building robust, molecular-scale electronics but have only been studied theoretically at the atomic level. Scanning tunneling microscopy was used to determine the atomic structure and electronic properties of such junctions in single-walled nanotube samples. Metal-semiconductor junctions are found to exhibit an electronically sharp interface without localized junction states, whereas a more diffuse interface and low-energy states are found in metal-metal junctions. Tight-binding calculations for models based on observed atomic structures show good agreement with spectroscopy and provide insight into the topological defects forming intramolecular junctions. These studies have important implications for applications of present materials and provide a means for assessing efforts designed to tailor intramolecular junctions for nanoelectronics.
单壁碳纳米管中的分子内结可能是构建坚固的分子级电子器件的理想结构，但目前仅在原子层面进行了理论研究。利用扫描隧道显微镜确定了单壁纳米管样品中此类结的原子结构和电子特性。研究发现，金属-半导体结呈现出电子性质尖锐的界面，不存在局域结态，而金属-金属结则具有更弥散的界面和低能态。基于观察到的原子结构建立的模型进行的紧束缚计算与光谱学结果吻合良好，有助于深入了解形成分子内结的拓扑缺陷。这些研究对现有材料的应用具有重要意义，并为评估旨在为纳米电子学定制分子内结的研究工作提供了一种方法。
