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Syntheses of Novel Metallofullerene Nano-Peapods

新型金属富勒烯纳米豆荚的合成

基本信息

批准号：
14204059
负责人：
SHINOBARA Hisashi
金额：
$ 30.12万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

项目摘要

One of the fascinating features of metallofullerene-peapods (CNT encaging fullerenes) such as Gd@C_<82> peapods is that we can perform a 'local band gap engineering' at the site where a fullerene is endothermally inserted. Previous TEM images and electron energy loss spectra suggested that the metallofullerenes can be spaced regularly as close as 1.1 nm in a high-density 'peapod' structure, while 1.1-3 nm spacing was often observed in a low-density peapod. In the present Gd@C_<82> peapod samples, about 10% of over 200 SWNT images showed locally modified semiconducting band gaps.Scanning tunneling microscopy and spectroscopy (dI/dY) give bias-dependent topographic images and local density of states (LDS) on carbon nanotubes near the fermi level. In the STS map, two strong VHS peaks corresponding to conduction and valence band edges are clearly seen with two smaller ones at higher bias voltages. The original band gap of 0.43 eV is narrowed down to 0.17 eV where the fullerene is expected to be located.Furthermore, Gd@C_<82> peapods exhibit ambipolar FET behavior with both n-and p-channels easily accessible by simple electrostatic gates. Similar results were obtained from more than 10 independent devices composed of a small bundle of Gd@C_<82> peapods. Such ambipolar behavior has never been observed for C_<60> peapods.TEM images and electron energy loss spectra suggested that the metallofullerenes can be spaced regularly as close as 1.1 nm in a high-density 'peapod' structure, while 1.1-3 nm spacing was often observed in a low-density peapod. In the present Gd@C_<82> peapod samples, about 10% of over 200 SWNT images showed locally modified semiconducting band gaps.

金属富勒烯-豆荚(碳纳米管包裹富勒烯)的一个吸引人的特点是，我们可以在富勒烯吸热插入的位置执行“局部带隙工程”。以前的电子显微镜图像和电子能量损失谱表明，在高密度豆荚结构中，金属富勒烯的间距可以规则地接近1.1 nm，而在低密度豆荚结构中，金属富勒烯的间距通常为1.1-3 nm。在目前的Gd@C&lt；82&gt；豆荚样品中，200多个SWNT图像中约有10%显示了局部修饰的半导体带隙。扫描隧道显微镜和能谱(Di/Dy)给出了偏置相关的形貌图像和碳纳米管上费米能级附近的局域态密度(LDS)。在STS图中，在较高的偏置电压下，可以清楚地看到对应于导带和价带边缘的两个较强的VHS峰和两个较小的VHS峰。原来0.43 eV的禁带宽度被缩小到0.17 eV，这是富勒烯应该位于的位置。此外，Gd@C_&lt；82&gt；豆荚具有双极型FET特性，n沟道和p沟道都很容易通过简单的静电门访问。从10多个独立的装置上也得到了类似的结果，这些装置由一小束Gd@C；82&gt；豆荚组成。电子显微镜图像和电子能量损失谱表明，在高密度的豆荚结构中，金属富勒烯的间距可以规则地接近1.1 nm，而在低密度的豆荚结构中，金属富勒烯的间距通常为1.1-3 nm。在目前的Gd@C&lt；82&gt；豆荚样品中，200多张SWNT图像中约有10%显示出局部修饰的半导体带隙。