Research Projects Supported by MEXT Through Special Subsidies for Private Universities and Institutions: Special Funds for the Creation of Strategic Research Infrastructure

Research Center for Green Electronic Devices and Materials

About

Established : 2014
Director: Professor Itaru Kamiya

Research Outline

Assuring the supply of resources and energy is becoming more and more difficult due to the boost of demands worldwide. Hence, reducing the consumption and more efficient use of energy are urgent issues that need to be solved in the industrially advanced nations inclusive of Japan. In particular, improving the efficiency of energy conversion instruments and devices, use of new energy resources, and reducing the energy consumption of the massively used IT instruments and lighting devices are imperative. In these instruments, devices, and materials, the operational principle and the loss are determined by their micro- and meso-scopic structures. Therefore, a quantum leap in their structure may lead to a drastic change in their electronic, optical, and thermal properties, thereby allowing us to realize novel materials and devices with advanced physical properties.

In view of such circumstances, we aim at developing technology that enable us to precisely control the structure of materials and devices to realize “Green Electronic Devices and Materials” that will allow us to significantly improve the efficiency of energy conversion instruments and devices, and reduce the power consumption of IT instruments.

Research Themes

・Development of highly efficient thermoelectric devices
・Ultra-low energy-consuming magnetic memories that will replace HDDs
・Electrode formation on single-layered graphene
・GaN-based high-power transistor that can withstand high voltage
etc.

Activities

1.Micro- & meso-structural control as a means for improving the properties of energy-related devices and materials 

In the thermoelectric devices, the structure of the alloy phases formed by addition of Mn and/or Al into Si needs to be controlled microscopically on an atomic scale.
In the photoelectric devices using the quantized states in nano-structures, the stoichiometry and the shape need to be controlled mesoscopically on the order of 10 nm.
Hence, we aim at establishing technology for controlling and fabricating structures that are controlled on micro- and meso-scales to realize materials and devices of the desired properties.

gedm01.png


2.”Developing Advanced Energy Conversion Devices and Materials” & “Reducing energy loss by control of interfaces and electrodes” 

gedm02.png

①Developing Advanced Energy Conversion Devices and Materials

In spite of their long history, the materials used for practical thermoelectric devices are limited to BiTe-based materials.  We have already discovered that SiMnAl-based alloys may have properties compatible to BiTe and that they may well turn into one of the strongest candidates for replacing Te-containing materials.  Here, we will focus on the improvement of their properties inclusive of the control of the thermal flow.
For the studies on photoelectron devices, we will used quantum dots, nanowires and/or nano-island structures that exhibit unique optical properties, and aim at improving the conversion efficiency and detection sensitivity.  Further, we will use GaN-based materials for realizing high power devices, transistors in particular, that can withstand high voltage.

gedm03.png

gedm04.png

②Reduction of power loss by advanced interface and electrodes

In many devices, the contact resistance at the electrode turns out to be one of the main sources of power loss and also limitation in the reliability.  We will try to modify and control the structure of interfaces and electrodes to reduce the loss while the carriers passes through the interfaces.  Focus will be placed on electrodes of GaN-based power devices where large currents flow, and graphene where the technique for forming stable electrodes is yet to be established.

gedm05.png

gedm06.png

gedm07.png

For the studies on electrodes for graphene, the first step is to prepare graphene sheets of large area.  We have already been successful in synthesizing mm-sized single crystal graphene.

gedm08.jpeg
mm-sized single crystal graphene
 

Participating Laboratories

 ・Quantum Interface Laboratory
 ・Energy Materials Laboratory
 ・Information Storage Materials Laboratory
 ・Surface Science Laboratory
 ・Advanced Electron Device Laboratory
 ・Semiconductor Laboratory


Equipments

・XPS
gedm09.jpeg

・Ar Ion Gun

・Automatic Versatile XRD
gedm10.jpeg

・Thermal Diffusivity Spectroscopy
Thermal-Diffusivity-Spectroscopy.jpg

・Thermal Characterization Instrument
Thermal-Characterization-Instrument.jpg

・AC/DC Magnetic Susceptibility Measuring Instrument

・Excimer Laser and Phololuminescence (PL) Mapper
gedm12.jpeg

・Semiconductor Etcher

page up