In this paper, my experience of over 30 years in carbon and carbon nanotube (CNT) research is reported. Moreover, an overview of the background of the catalytic chemical vapor deposition process for CNT synthesis, the present status of CNT technology toward safe innovation based on the promotion of a precautionary approach, and the future of CNT science are described.

Breakthroughs and challenges are overviewed in a twenty-year history of carbon nanotubes and graphene. In the field of nanotubes, metallic and semiconducting carbon nanotubes can be separated and the application of nanotubes to devices has significantly advanced. In the case of graphene, because of its unique electronic properties, its application to devices operated at a high frequency is promising.

The so-called nanocarbon materials (which include fullerenes, metallofullerenes, carbon nanotubes, peapods and graphene) have been discovered, macroscopically synthesized and characterized during the past 20 years. After reviewing the history of nanocarbons briefly, the synthesis and characterization of a couple of novel nanocarbon materials, peapods and nanowire-encapsulating carbon nanotubes, are described in terms of their unique structural and electronic properties. In particular, metallofullerenes-peapods show the local band-gap modulation which have never been observed in the pristine carbon nanotubes, suggesting that the peapods can be applied to channels of future nano-electronic devices.

Catalytic chemical vapor deposition (CVD) using alcohol (ACCVD method) has become the most popular technique of growing single-walled carbon nanotubes (SWNTs) because it produces high-quality and high-purity SWNTs in a wide temperature range and even at low gas pressures. SWNTs of various morphologies can be directly grown on substrates for device applications. Vertically aligned, horizontally aligned, and suspended growth processes of various patterns are realized. In situ observations and the exploration of new catalysts are being conducted. Furthermore, ACCVD technique is applied to other nanocarbon materials, such as double-walled CNTs and graphene.

Graphene, a single-layer hexagonal network of carbon atoms, has recently attracted considerable interest owing to the extremely high carrier mobility and behaviors of massless Dirac fermions. Because graphene is very sensitive to environmental conditions, chemical and biological sensors using graphene are promising materials for biochips used at home for medical diagnosis. In this paper, the potentiality of graphene field-effect transistors for sensor application is described.

We review our studies on passively mode-locked fiber lasers and nonlinear optical devices using carbon nanotubes (CNTs). CNT-based devices offer several key advantages, such as ultrafast response, robustness, the tunability of wavelength, and compatibility to fibers.

We studied the effect of the work function of a contact metal on the conduction type of carbon nanotube field-effect transistors (CNT-FETs). We also analyzed the results of chemical doping using tetrafluorotetracyanoquinodimethane (F₄TCNQ). Moreover, we described the preferential growth of CNTs with semiconducting behavior in the FET current-voltage characteristics and its application to thin film transistors. Considering the application of CNT-FETs to future complementary metal-oxide-semiconductor large-scale integrated circuits, we examined the growth of high-density horizontally aligned CNTs for a high drive current and the fabrication of n-channel CNT-FETs employing interface fixed charges.

Single wall carbon nanotubes are damaged by irradiation of electrons or photons whose energy is several electron volts to several ten kiloelectron volts (low-energy irradiation damage). Therefore, it is necessary to pay attention to the damage when we use analytical tools equipped with an electron gun or a vacuum ultraviolet light source. In this article, some characteristics of low-energy irradiation damage and its defect properties are summarized. Metal-semiconductor transition of the electric properties induced by defects is also discussed.

Single-wall carbon nanohorns (SWNHs) have a unique aggregate structure which is advantageous for supporting fine particles of a platinum catalyst for fuel cell electrodes. The power density of the fuel cell was markedly increased by using SWNHs as catalyst supports. The large-scale production of SWNHs, which is indispensable for industrial applications, is also described in detail.

Carbon nanomaterials, such as carbon nanotubes and nanohorns, have been studied for anticancer treatment over the past years. Their advantage for drug delivery system application is that they can be multifunctionalized by chemical and physical modifications. We introduce the current researches of anticancer treatments with carbon nanotubes and nanohorns in this article.

Entanglement is the essence of quantum information and communication technology. An introductory tutorial of entanglement is presented for beginners.