Development of energy materials based on understanding and controlling their properties in nano scale
–from crystal growth to device design–

Applying academic and knowledge of conventional metallurgical thermodynamics to advanced materials including semiconductors, searching environmentally harmonious new materials and working to solve energy and environmental problems from the viewpoint of material science through construction of new device structure I will.

Understanding and control of interface structure in energy generation device

There are various hetero (hetero phase) interfaces in energy generation devices such as solar cells. In order to improve the performance of the device, it is necessary to optimize the structure and characteristics at the interface between materials, in addition to controlling the physical properties of the various materials that make up the device. For example, in a solar cell device, it is necessary to select a material that properly connects the level of the bottom of the conduction band at the interface between the two materials (light absorption layer material and buffer layer material) that make up the pn junction.
The group will clarify device design guidelines by clarifying these level relationships using methods such as photoelectron spectroscopy. In addition, the interface between the metal serving as an electrode and the light absorbing layer material is also important.
It must be designed to be an ohmic junction at this interface. In addition to choosing the right material, we will analyze the reaction at the interface based on thermodynamics, leading to higher performance of the device.
[J Mater. Chem. C, (2017); ACS Appl. Mater. Inter., (2017)]

The left figure shows the current-voltage characteristics of the junction between Zn3P2 and Al or Ag. The work function of Al and Ag is almost the same, but the behavior of the current-voltage characteristics of both are different.
This is due to the fact that compound semiconductors are formed as an intermediate layer in Al, but not in Ag.

Contact us:
Department of Materials Science and Engineering Kyoto University
Yoshida-Honmachi, Sakyo-ku Kyoto 606-8501
Engineering Science Depts Bldg.7F
(tel) 075-753-5472 (Nose)
(fax) 075-753-3579 (Lab.)