The discovery of CNTs in 1991[1] was very much owing to high resolution electron microscopy (HRTEM) which I have been engaging in from its early development[2]. In this connection I would like to present the most recent achievement in HRTEM that has been realized at an atom resolution level by Energy dispersive X-ray spectrometry (EDS). Such a new technology should be extremely important for nanoscience and nanotechnology. 

The carbon nanotubes brought us dual excitements in both academia as condensed matter physics and industrial applications. Such a broad range of the attraction is reflected in an extremely high Google citation, its number becoming over 47,000 only for the first paper reporting CNT in 1991. The number is still increasing even after 27 years of the discovery. I would like to introduce some my own effort in attempt of CNT device applications.

CNT, chrysotile asbestos, imogolite [3], and many structures in biological systems are known to have tubular structures, resulting from anisotropic growth in one particular orientation. In the case of CNT, the presence of catalytic metal particles in the tubule formation appears to control a tubular morphology. We have recently examined aluminum oxy-hydroxide gamma-AlOOH, boehmite, which has been known to form into a variety of morphologies from a fibril, low-dimensional sheet, platelets, to bulk crystal, depending on a synthesis process. One of them is a quasi-one-dimensional fibril structure, which grows in an aqueous solution as a sol form. We have studied detailed morphology of this fibril boehmite and found that the fibril grows selectively parallel to the c-axis and does not form in a tubular structure but a nanometer-sized ribbon [4]. Electronic energy band gaps of such a ribbon have been studied and showed interesting size-dependent band gaps [5]. The growth was not promoted by a particular catalytic substance so that such an anisotropic growth should be originated from the boehmite structure itself and surroundings.

1)S. Iijima, Nature, 345, 56-58 (1991).

2)S. Iijima, J. Appl. Phys., 42, 5891-5893 (1971).

3)K. Wada et al., Amer. Mineral., 54, 50 (1969).

4)S. Iijima et al., PNAS, 113, 11759-11764 (2016).

5)M. Toyoda & S. Saito, private communication 2018.

The discovery of CNTs in 1991[1] was very much owing to high resolution electron microscopy (HRTEM) which I have been engaging in from its early development[2]. In this connection I would like to present the most recent achievement in HRTEM that has been realized at an atom resolution level by Energy dispersive X-ray spectrometry (EDS). Such a new technology should be extremely important for nanoscience and nanotechnology. 

The carbon nanotubes brought us dual excitements in both academia as condensed matter physics and industrial applications. Such a broad range of the attraction is reflected in an extremely high Google citation, its number becoming over 47,000 only for the first paper reporting CNT in 1991. The number is still increasing even after 27 years of the discovery. I would like to introduce some my own effort in attempt of CNT device applications.

CNT, chrysotile asbestos, imogolite [3], and many structures in biological systems are known to have tubular structures, resulting from anisotropic growth in one particular orientation. In the case of CNT, the presence of catalytic metal particles in the tubule formation appears to control a tubular morphology. We have recently examined aluminum oxy-hydroxide gamma-AlOOH, boehmite, which has been known to form into a variety of morphologies from a fibril, low-dimensional sheet, platelets, to bulk crystal, depending on a synthesis process. One of them is a quasi-one-dimensional fibril structure, which grows in an aqueous solution as a sol form. We have studied detailed morphology of this fibril boehmite and found that the fibril grows selectively parallel to the c-axis and does not form in a tubular structure but a nanometer-sized ribbon [4]. Electronic energy band gaps of such a ribbon have been studied and showed interesting size-dependent band gaps [5]. The growth was not promoted by a particular catalytic substance so that such an anisotropic growth should be originated from the boehmite structure itself and surroundings.

1)S. Iijima, Nature, 345, 56-58 (1991).

2)S. Iijima, J. Appl. Phys., 42, 5891-5893 (1971).

3)K. Wada et al., Amer. Mineral., 54, 50 (1969).

4)S. Iijima et al., PNAS, 113, 11759-11764 (2016).

5)M. Toyoda & S. Saito, private communication 2018.