Research on Organic Thin-film Devices and Hydrogen Generation Devices

The Noda Research Lab of Keio University’s Department of Electronics and Electrical Engineering is conducting research with the goal of creating new electronic devices that will become next-generation foundational technology, using various electronic materials such as organic semiconductors and oxide semiconductors.

"With regard to organic materials, there are a number of examples of application. One of the main areas we are researching is to create a device known as an organic transistor and to perform property evaluation of the device itself. This organic transistor, which uses film made of an organic semiconductor, can be used as a switching device that regulates current flowing in the film according to the amount of voltage applied to a third electrode known as a gate. Today, all electronic devices operate using CMOS transistors, but now there is much research being conducted everywhere to get organic semiconductors to operate with the same functionality as CMOS transistors. There are still many issues that remain before organic transistors can become commercialized, so we are conducting research to overcome these issues."

The Noda Research Lab is also proposing new evaluation methods and conducting applied research on the physical quantity of carrier transport in organic semiconductors, in other words the carrier mobility or carrier concentration.

"As for carrier mobility, the values can vary quite a bit depending on how measurements are conducted. To properly conduct property evaluation, we are investigating these methods and samples to establish an evaluation method so that reliable values are obtained if measured in a certain way. As for carrier concentration, the measurement method for carrier concentration in organic semiconductors has still not been well established. On the other hand, carrier doping is now the subject of great focus, so we are developing doping technology and also conducting research especially on how to effectively measure carrier concentration."

In recent years, power sources that use hydrogen have garnered attention as renewable energy systems. The Noda Research Lab is actively using water, which is available in unlimited amounts in nature; bio fuels such as ethanol that can be produced from plants; and solar energy, with the goal of creating and applying a new clean energy source in the form of hydrogen energy.

"There is a lot of research being conducted around the world on utilizing solar energy in an effort to derive hydrogen and oxygen from water, but this still presents difficulties because of the inability to increase efficiency sufficiently. So another method being researched is to mix alcohol with water, and then transforming solar energy into hydrogen. What makes this energy transformation possible is the photocatalytic function of oxide semiconductor materials. So if this function can be utilized effectively to develop a miniaturized hydrogen generation source, since the creation of a hydrogen-energy-based society that uses fuel cells is being widely advocated right now, we are conducting research."

The Noda Research Lab will continue to take an ongoing approach toward these research issues. Through ideas and applied research of new devices looking 10 years and 20 years ahead, as well as through fundamental research of new property evaluation methods of various electronic materials, the laboratory aims to contribute to development of new electronic materials and devices, and the forthcoming hydrogen energy society. To this end it will continue to conduct active research and educational projects.