Kochi University of Technology

Materials Design Center

A pioneering material design domain based on our design methodology　for solving　problems related to wide band gap semiconductors, electrical properties in oxide semiconductors, optical properties, and magnetic characteristic control method (EOM).

Three major objectives of the Materials Design Center

1. Pioneering work on 21st century materials, through research and development of equipment with high potential to support innovative work with these materials (e.g. film fabrication apparatus).
   Continuing work is necessary, since even though silicon (Si), Gallium nitride (GaN) and indium tin oxide (ITO) materials for semiconductors have been supporting 20th century industry, there are some issues to be resolved, such as high temperature in film fabrication, scarcity of resources and high cost.
2. To arrive at solutions to these problems, we are using a systematic approach and methodology for property control, rather than the usual method with its partial reliance on chance success.
3. Conducting research and development towards commercialization, we are collaborating with companies and evolving our own collaboration style.

By finding a strong correlation between important success factors for industry, such as low cost and low power consumption; and important success factors for research and development, we will be able to eliminate the boundary between basic research and practical research and eventually formulate a design base which can consistently play leading edge roles in research and development.

One typical case of realization of this objective is the development of transparent conductive film, using zinc oxide (ZnO) as material.

In applications of transparent conductive film (e.g. for liquid crystal displays, plasma displays and thin film solar cells), indium tin oxide (ITO) is used. However, indium is an extremely expensive and rare material. Professor Yamamoto has focused attention on zinc oxide (ZnO) as an alternative to ITO. Compared to indium, zinc is widely available and inexpensive, and theoretically is almost the equal of indium in characteristics such as electric resistance and permeability.

Professor Yamamoto organized an industry-government-academia consortium and performed repeated experiments to laminate zinc oxide molecules onto a glass substrate using plasma energy and enhanced equipment. Eventually he succeeded, and was the first in the world to produce large size ZnO transparent conductive film (one meter square) with capacity comparable to that ITO transparent conductive film. It is expected that his method will eventually reduce the production cost to less than half of the present level, since membrane production can be done at lower temperature than other technologies.

Currently, the Center is engaged in research and development as a Japan Science and Technology Agency joint research project for local collaboration, with companies such as Casio Computer, aiming to develop further applications of zinc oxide.

In research and development, it is always important to conduct research with a ‘systematic’ policy, rather than with the expectation for chance success throughout the stages of emergence, growth and expansion, and maturity. For example, one feature of the Center is that it has been pioneering a method embodying a constructive concept in parallel with research in research and development toward the realization of a P-type semiconductor using zinc oxide.

In the near future, I intend to demonstrate experimentally the effectiveness of the ‘simultaneous doping theory’ which I have developed. Simultaneous doping can control things such as dielectric constant and effective mass by systematically doping the acceptor and donor. This method is expected to have applications in other fields as well as the semiconductor field.

Professor Tetsuya Yamamoto
Director of the Material Design Center