EE Distinguished Lecturer Seminar - 2014 Physics Nobel Prize: GaN as a key material for establishing a sustainable society
Event details
| Date | 14.10.2019 |
| Hour | 12:15 › 13:15 |
| Speaker | Hiroshi Amano received his BE, ME and DE degree in 1983, 1985 and 1989, respectively, from Nagoya University. From 1988 to 1992, he was a research associate at Nagoya University. In 1992, he moved to MeijoUniversity, where he was an assistant professor, associate professor from 1998 till 2002, and professor from 2002 till 2010. He moved to Nagoya University, where he was a professor of Graduate School of Engineering from 2011 till 2015. On Oct. 1, 2015, he became a director of Center for Integrated Research of Future Electronics, Institute of Materials and Systems for Sustainability, Nagoya University. During his doctoral program at the Nagoya University Graduate School of Engineering, he was able to realize high-quality epitaxially grown GaN film with metal-organic vapor phase epitaxy (MOVPE), p-type GaN filmdoped with Mg while conducting research with Professor Akasaki.For the first time in history, he established the technology necessary for the production of blue LEDs, thus performing a great achievement the development of the high-luminosity blue LED. He is currently developing technologies for the fabrication of high-efficiency power semiconductor development and new energy-saving devices at Nagoya University. He has over 560 publications. Prof. Amano shared the Nobel Prizein Physics 2014 with Prof. Isamu Akasaki and Prof. Shuji Nakamura "for the invention of efficient blue light-emitting diodes which has enabled bright and energy-saving white light sources" |
| Location | |
| Category | Conferences - Seminars |
Abstract : The most important application of III nitrides is blue LEDs for full color displays and general lighting systems. Most of the commercially available blue are grown on foreign substrates such as sapphire, Si or SiC. In spite of high dislocation density over 108cm-2, wall plug efficiency (WPE) of blue LEDs exceeds 50%, which is extremely high compared with that of LEDs made by other III-V compound semiconductors such as GaAs or GaP. In case of other LEDs, WPE may be less than 1% if such a high density of dislocations exists in the crystal.One of the reason of high-efficiency of blue LEDs based on III nitrides is short diffusion length of minority carriers in GaN and InGaN. By 2020, more than 70% of the general lighting system will be replaced from the conventional incandescent lamps or fluorescent lamps to LED lamps, by which about 7% of the total electricity consumption can be saved. In this presentation, history and future prospects of the development of the blue LEDs will be discussed.
AlGaN-based deep-UV (DUV) LEDs on sapphire substrates are effective for the efficient and long-life devices for sterilization and purification of water compared with conventional UV germicidal lamps. UNICEF reported that 844 million people still lack access to safe drinking water and 2.3 billion people do not use safe sanitation facilities. New water sterilization and purification systems have been commercialized, in which AlGaN-based high-power DUV LEDs are installed. Other applications of DUV LEDs include as a sterilizer for sanitation facilities, resins and the curing of inks in large printers, detecting forged banknotes, photolithography for manufacturing semiconductor devices, and treating skin disease, which is called dermatology.
Microwave high-electron mobility transistors (HEMT) based on AlGaN/GaN on SiC substrate works well in spite of high dislocation density over 108cm-2because high-density two-dimensional electron gas induced by polarization of these materials is used, therefore Fermi level in the channel layer is very high and scattering by the dislocation is small. Majority of high-power amplifier in base station of smart phone have been replaced from multichip GaAs-based HEMT to single chip GaN-based HEMT.
Breakdown field of GaN is one order of magnitude higher than that of Si. Therefore, we can reduce not only the size of the transistors, but also power loss to one tenth. If we replace all the Si based transistors such as insulated gate bipolar transistors to GaN based transistors in the invertor circuits, we can reduce 9.8% of the total electricity consumption in Japan. For power device applications, vertical structure is more feasible to operate high current. Low defect density crystal is essential for realizing low current leakage at high voltage. Therefore, requirement specification for the substrate and epitaxial layer is much higher than that of LEDs and microwave devices. In this presentation, substrate and epitaxy issues for the future power devices based on III nitrides will be discussed.
This research is supported by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan, through its “Program for research and development of next-generation semiconductor to realize energy-saving society.
AlGaN-based deep-UV (DUV) LEDs on sapphire substrates are effective for the efficient and long-life devices for sterilization and purification of water compared with conventional UV germicidal lamps. UNICEF reported that 844 million people still lack access to safe drinking water and 2.3 billion people do not use safe sanitation facilities. New water sterilization and purification systems have been commercialized, in which AlGaN-based high-power DUV LEDs are installed. Other applications of DUV LEDs include as a sterilizer for sanitation facilities, resins and the curing of inks in large printers, detecting forged banknotes, photolithography for manufacturing semiconductor devices, and treating skin disease, which is called dermatology.
Microwave high-electron mobility transistors (HEMT) based on AlGaN/GaN on SiC substrate works well in spite of high dislocation density over 108cm-2because high-density two-dimensional electron gas induced by polarization of these materials is used, therefore Fermi level in the channel layer is very high and scattering by the dislocation is small. Majority of high-power amplifier in base station of smart phone have been replaced from multichip GaAs-based HEMT to single chip GaN-based HEMT.
Breakdown field of GaN is one order of magnitude higher than that of Si. Therefore, we can reduce not only the size of the transistors, but also power loss to one tenth. If we replace all the Si based transistors such as insulated gate bipolar transistors to GaN based transistors in the invertor circuits, we can reduce 9.8% of the total electricity consumption in Japan. For power device applications, vertical structure is more feasible to operate high current. Low defect density crystal is essential for realizing low current leakage at high voltage. Therefore, requirement specification for the substrate and epitaxial layer is much higher than that of LEDs and microwave devices. In this presentation, substrate and epitaxy issues for the future power devices based on III nitrides will be discussed.
This research is supported by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan, through its “Program for research and development of next-generation semiconductor to realize energy-saving society.
Practical information
- General public
- Free
Organizer
- Elison Matioli / Nicolas Grandjean
Contact
- [email protected] / +4121 69 33721 [email protected] / +4121 69 33444