Isamu Akasaki (赤崎 勇, Akasaki Isamu; January 30, 1929 – April 1, 2021) was a Japanese materials scientist specializing in the field of semiconductor technology. He is best known for co-inventing the bright gallium nitride (GaN) p–n junction blue LED in 1989 and subsequently the high-brightness GaN blue LED as well. Akasaki was awarded the 2014 Nobel Prize in Physics, along with Hiroshi Amano and Shuji Nakamura, "for the invention of efficient blue light-emitting diodes which has enabled bright and energy-saving white light sources."
Early life and education Isamu Akasaki was born on January 30, 1929, in Chiran, Japan, and was raised in Kagoshima. His elder brother is Masanori Akazaki, who was an electronic engineering researcher and a Professor Emeritus at Kyushu University. (Their surname "赤﨑" is also pronounced Akazaki.) Akasaki graduated from Kagoshima Prefectural Daini-Kagoshima Middle School (now Kagoshima Prefectural Konan High School) in 1946, from Seventh Higher School Zoshikan (now Kagoshima University) in 1949, and from the Faculty of Science at Kyoto University in 1952. During his university years, he visited shrines and temples that local residents rarely visit, walked around the mountains of Shinshu during the summer vacation, enjoyed classes and enjoyed a fulfilling student era.
Career
In 1952, Akasaki joined the research staff of the Kobe Kogyo Corporation (now Fujitsu Ltd.). From 1959 to 1964, he worked at Nagoya University, where he was Research Associate, Assistant Professor, and Associate Professor in the Department of Electronics. In 1964, he obtained a D.Eng. from Nagoya for a thesis on the vapor-phase epitaxial growth of Ge. After receiving his doctorate, he joined Matsushita Research Institute Tokyo, Inc., where he became head of the Basic Research Laboratory IV and then general manager of the Semiconductor Department. In 1981, Akasaki returned to Nagoya University as a professor. In 1992, Akasaki became a professor in the Graduate School of Science and Technology at Meijo University. He was appointed director of the Research Center for Nitride Semiconductor Core Technologies in 2011. From 1987 to 1990, Akasaki was a project leader of "Research and Development of GaN-based Blue Light–Emitting Diode" sponsored by the Japan Science and Technology Agency (JST). He then led the "Research and Development of GaN-based Short-Wavelength Semiconductor Laser Diode" product sponsored by JST from 1993 to 1999. While he led this project, he was also a visiting professor at the Research Center for Interface Quantum Electronics at Hokkaido University, from 1995 to 1996. In 1996 he was a project leader of the Japan Society for the Promotion of Science's for the "Future program" up to 2001. From 1996 he started as a Project Leader of "High-Tech Research Center for Nitride Semiconductors" at Meijo University, sponsored by MEXT until 2004. From 2003 up to 2006 he was the chairman of "R&D Strategic Committee on the Wireless Devices Based on Nitride Semiconductors" sponsored by METI.
Research Akasaki started working on GaN-based blue LEDs in the late 1960s. Step by step, he improved the quality of GaN crystals and device structures at Matsushita Research Institute Tokyo, Inc. (MRIT), where he decided to adopt metalorganic vapor phase epitaxy (MOVPE) as the preferred growth method for GaN. In 1981, Akasaki started afresh the growth of GaN by MOVPE at Nagoya University, and in 1985 he and his group succeeded in growing high-quality GaN on sapphire substrate by pioneering the low-temperature (LT) buffer layer technology. This high-quality GaN enabled them to discover p-type GaN by doping with magnesium (Mg) and subsequent activation by electron irradiation (1989), to produce the first GaN p-n junction blue/UV LED (1989), and to achieve conductivity control of n-type GaN (1990) and related alloys (1991) by doping with silicon (Si), enabling the use of hetero structures and multiple quantum wells in the design and structure of more efficient p-n junction light emitting structures. They achieved stimulated emission from the GaN firstly at room temperature in 1990, and developed in 1995 the stimulated emission at 388 nm with pulsed current injection from high-quality AlGaN/GaN/GaInN quantum well device. They verified quantum size effect (1991) and quantum confined Stark effect (1997) in nitride system, and in 2000 showed theoretically the orientation dependence of piezoelectric field and the existence of non-/semi-polar GaN crystals, which have triggered today's worldwide efforts to grow those crystals for application to more efficient light emitters.
Nagoya University Akasaki Institute
Akasaki's patents were produced from these inventions, and the patents have been rewarded as royalties. Nagoya University Akasaki Institute opened on October 20, 2006. The cost of construction of the institute was covered with the patent royalty income to the university, which was also used for a wide range of activities in Nagoya University. The institute consists of an LED gallery to display the history of blue LED research/developments and applications, an office for research collaboration, laboratories for innovative research, and Akasaki's office on the top sixth floor. The institute is situated in the center of the collaboration research zone in Nagoya University Higashiyama campus.
Personal life He and his wife Ryoko lived in Nagoya, and the couple had no children.
Death Akasaki died from pneumonia at a hospital in Nagoya on April 1, 2021, at the age of 92.
Recognition
Awards
Memberships
Honors
See also List of Japanese Nobel laureates List of Nobel laureates affiliated with Kyoto University
Notes
References
Further reading Insights & Enterprise in PHOTONICS SPECTRA, 54, November 2004. Materials Research Society Symposium Proceedings, Volume 639 (2000), pp. xxiii–xxv.
External links Nobel Prize website Isamu Akasaki on Nobelprize.org Compound Semiconductor (pp. 17–19) New York Times obituary: “Nobel winner lit up the world with LEDs” (April 2021). "Spotlight on Nagoya". Nature. October 7, 2009. doi:10.1038/nj0264.
