Isamu Akasaki
赤﨑 勇
Isamu Akasaki 201111.jpg
Isamu Akasaki
Born(1929-01-30)January 30, 1929
DiedApril 1, 2021(2021-04-01) (aged 92)
Nagoya, Aichi, Japan
Alma materKyoto University
Nagoya University
AwardsAsahi Prize (2001)
Takeda Award (2002)
Kyoto Prize (2009)
IEEE Edison Medal (2011)
Nobel Prize in Physics (2014)
Charles Stark Draper Prize (2015)
Scientific career
FieldsPhysics, Engineering
InstitutionsMeijo University
Nagoya University

Isamu Akasaki (赤﨑 勇, Akasaki Isamu, January 30, 1929 – April 1, 2021) was a Japanese engineer and physicist, specializing in the field of semiconductor technology and Nobel Prize laureate, best known for inventing the bright gallium nitride (GaN) p-n junction blue LED in 1989 and subsequently the high-brightness GaN blue LED as well.[1][2][3][4][5]

For this and other achievements, Akasaki was awarded the Kyoto Prize in Advanced Technology in 2009,[6] and the IEEE Edison Medal in 2011.[7] He was also awarded the 2014 Nobel prize in Physics, together with Hiroshi Amano and Shuji Nakamura,[8] "for the invention of efficient blue light-emitting diodes, which has enabled bright and energy-saving white light sources". In 2021, Akasaki, along with Shuji Nakamura, Nick Holonyak, M. George Craford and Russell D. Dupuis were awarded the Queen Elizabeth Prize for Engineering "for the creation and development of LED lighting, which forms the basis of all solid state lighting technology".[9]

Early life and education

Isamu Akasaki
Isamu Akasaki

He was born in Chiran, Kagoshima Prefecture and raised in Kagoshima City.[10][11] His elder brother is Masanori Akazaki [ja] who was an electronic engineering researcher and a Professor Emeritus at Kyushu University.[11] (Their surname "赤﨑" is also pronounced Akazaki.[12][13])

Isamu 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[11] and from Department of Chemistry, Faculty of Science, Kyoto University in 1952.[10] 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.[10] After he became a researcher, he obtained the degree of Doctor of Engineering from Nagoya University in 1964.[14]


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[15] 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 he 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.[16][17]

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)[18] and related alloys (1991)[19] 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,[20] and developed in 1995 the stimulated emission at 388 nm with pulsed current injection from high-quality AlGaN/GaN/GaInN quantum well device.[21] They verified quantum size effect (1991)[22] and quantum confined Stark effect (1997)[23] in nitride system, and in 2000 showed theoretically the orientation dependence of piezoelectric field and the existence of non-/semi-polar GaN crystals,[24] which have triggered today's worldwide efforts to grow those crystals for application to more efficient light emitters.

Nagoya University Akasaki Institute

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Akasaki Institute
Akasaki Institute

Akasaki's patents were produced from these inventions, and the patents have been rewarded as royalties. Nagoya University Akasaki Institute[25] 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.

Professional record

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with Seiji Morimoto (in Sweden)

Akasaki worked as a Research Scientist from 1952 to 1959 at Kobe Kogyo Corporation (now, Fujitsu Ltd.).[26] In 1959 he was a research associate, assistant professor, and associate professor at the Department of Electronics at Nagoya University until 1964. Later in 1964, he was the Head of Basic Research Laboratory at Matsushita Research Institute Tokyo, Inc. until 1974 to later become a General Manager of Semiconductor Department (in the same institute until 1981).[citation needed] In 1981 he became a professor in the Department of Electronics at Nagoya University until 1992.[26]

From 1987 to 1990 he was a Project Leader of "Research and Development of GaN-based Blue Light–Emitting Diode" sponsored by 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.

He continued working as a Professor Emeritus of Nagoya University, Professor of Meijo University from 1992.[26] He was also the Director of the Research Center for Nitride Semiconductors at Meijo University since 2004. He also worked as a Research Fellow at Akasaki Research Center of Nagoya University from 2001.


Akasaki died of pneumonia, on April 1, 2021, aged 92.[27]

Honors and awards

Scientific and academic

with Shuji Nakamura and Hiroshi Amano (at the Grand Hôtel on December 8, 2014)
with Shuji Nakamura and Hiroshi Amano (at the Grand Hôtel on December 8, 2014)


Akasaki received the Order of Culture. After that, they posed for the photo. (at the East Garden of the Tokyo Imperial Palace on November 3, 2011)
Akasaki received the Order of Culture. After that, they posed for the photo. (at the East Garden of the Tokyo Imperial Palace on November 3, 2011)

See also


  1. ^ Isamu Akasaki and Hiroshi Amano (2006). "Breakthroughs in Improving Crystal Quality of GaN and Invention of the p–n Junction Blue-Light-Emitting Diode". Japanese Journal of Applied Physics. 45 (12): 9001–9010. Bibcode:2006JaJAP..45.9001A. doi:10.1143/JJAP.45.9001. S2CID 7702696. Archived from the original on July 22, 2012. Retrieved November 10, 2015.((cite journal)): CS1 maint: uses authors parameter (link)
  2. ^ "Japanese Journal of Applied Physics". Archived from the original on April 18, 2012. Retrieved November 10, 2015.
  3. ^ Amano, Hiroshi; Kito, Masahiro; Hiramatsu, Kazumasa; Akasaki, Isamu (December 20, 1989). "P-Type Conduction in Mg-Doped GaN Treated with Low-Energy Electron Beam Irradiation (LEEBI)". Japanese Journal of Applied Physics. Japan Society of Applied Physics. 28 (Part 2, No. 12): L2112–L2114. Bibcode:1989JaJAP..28L2112A. doi:10.1143/jjap.28.l2112. ISSN 0021-4922.
  4. ^ Isamu Akasaki; Hiroshi Amano; Masahiro Kito; Kazumasa Hiramatsu (1991). "Photoluminescence of Mg-doped p-type GaN and electroluminescence of GaN p-n junction LED". Journal of Luminescence. Elsevier BV. 48–49: 666–670. Bibcode:1991JLum...48..666A. doi:10.1016/0022-2313(91)90215-h. ISSN 0022-2313.
  5. ^ Isamu Akasaki, Hiroshi Amano, Kenji Itoh, Norikatsu Koide and Katsuhide Manabe: "GaN-based UV/blue light emitting devices", Inst. Phys. Conf. Ser. No.129, pp. 851-856, 1992
  6. ^ "Kyoto Prize: Isamu Akasaki". Inamori Foundation. Archived from the original on March 4, 2016. Retrieved November 10, 2015.
  7. ^ a b "IEEE Jack S. Kilby Signal Processing Medal Recipients" (PDF). IEEE. Retrieved April 15, 2012.
  8. ^ a b "The 2014 Nobel Prize in Physics - Press Release". Nobel Media AB 2014. Retrieved October 7, 2014.
  9. ^ "LED Lighting". Queen Elizabeth Prize for Engineering.
  10. ^ a b c "ノーベル物理学賞受賞者・赤﨑勇博士と京都大学 -大学時代に育まれた研究者の芽-" (in Japanese). Kyoto University. Retrieved 2021-09-05.
  11. ^ a b c 赤﨑勇(AKASAKI Isamu)"青い光に魅せられて 青色LED開発物語",Japan:日本経済新聞出版社(Nikkei Business Publications),2013
  12. ^ "Asia University Summit pp.7-8" (PDF). Aichi Prefectural Government. 2021. Retrieved 2022-06-27.
  13. ^ Juichi Yamagiwa (2015-07-16). "Welcome Speech by Juichi Yamagiwa, Dr. of Science, President of Kyoto University - UNESCO International Scientific Symposium Kyoto University, 16 July, 2015" (PDF). Kyoto University OCW (Open Course Ware). Kyoto University. p. 2. Retrieved 2022-06-27.
  14. ^ "赤崎 勇「Geの気相成長に関する研究」". CiNii (in Japanese). National Institute of Informatics (Japan). Retrieved 2022-06-27.
  15. ^ Y. Ohki, Y. Toyoda, H. Kobayasi and I. Akasaki: "Fabrication and properties of a practical blue-emitting GaN m-i-s diode. Inst. Phys. Conf. Ser. No. 63, pp. 479-484 (Proc. of the 9th Intl. Symposium on Gallium Arsenide and Related Compounds, 1981).
  16. ^ Amano, H.; Sawaki, N.; Akasaki, I.; Toyoda, Y. (February 3, 1986). "Metalorganic vapor phase epitaxial growth of a high quality GaN film using an AlN buffer layer". Applied Physics Letters. AIP Publishing. 48 (5): 353–355. Bibcode:1986ApPhL..48..353A. doi:10.1063/1.96549. ISSN 0003-6951.
  17. ^ Akasaki, Isamu; Amano, Hiroshi; Koide, Yasuo; Hiramatsu, Kazumasa; Sawaki, Nobuhiko (1989). "Effects of ain buffer layer on crystallographic structure and on electrical and optical properties of GaN and Ga1−xAlxN (0 < x ≦ 0.4) films grown on sapphire substrate by MOVPE". Journal of Crystal Growth. Elsevier BV. 98 (1–2): 209–219. doi:10.1016/0022-0248(89)90200-5. ISSN 0022-0248.
  18. ^ H. Amano and I. Akasaki: "Fabrication and Properties of GaN p-n Junction LED", Mater. Res. Soc. Extended Abstract (EA-21), pp.165-168, 1990, (Fall Meeting 1989)
  19. ^ Murakami, Hiroshi; Asahi, Tsunemori; Amano, Hiroshi; Hiramatsu, Kazumasa; Sawaki, Nobuhiko; Akasaki, Isamu (1991). "Growth of Si-doped AlxGa1–xN on (0001) sapphire substrate by metalorganic vapor phase epitaxy". Journal of Crystal Growth. Elsevier BV. 115 (1–4): 648–651. Bibcode:1991JCrGr.115..648M. doi:10.1016/0022-0248(91)90820-u. ISSN 0022-0248.
  20. ^ Amano, Hiroshi; Asahi, Tsunemori; Akasaki, Isamu (February 20, 1990). "Stimulated Emission Near Ultraviolet at Room Temperature from a GaN Film Grown on Sapphire by MOVPE Using an AlN Buffer Layer". Japanese Journal of Applied Physics. Japan Society of Applied Physics. 29 (Part 2, No. 2): L205–L206. Bibcode:1990JaJAP..29L.205A. doi:10.1143/jjap.29.l205. ISSN 0021-4922. S2CID 120489784.
  21. ^ Akasaki, Isamu; Amano, Hiroshi; Sota, Shigetoshi; Sakai, Hiromitsu; Tanaka, Toshiyuki; Koike, Masayoshi (November 1, 1995). "Stimulated Emission by Current Injection from an AlGaN/GaN/GaInN Quantum Well Device". Japanese Journal of Applied Physics. Japan Society of Applied Physics. 34 (11B): L1517–L1519. Bibcode:1995JaJAP..34L1517A. doi:10.7567/jjap.34.l1517. ISSN 0021-4922. S2CID 122963134.
  22. ^ Itoh, Kenji; Kawamoto, Takeshi; Amano, Hiroshi; Hiramatsu, Kazumasa; Akasaki, Isamu (September 15, 1991). "Metalorganic Vapor Phase Epitaxial Growth and Properties of GaN/Al0.1Ga0.9N Layered Structures". Japanese Journal of Applied Physics. Japan Society of Applied Physics. 30 (Part 1, No. 9A): 1924–1927. Bibcode:1991JaJAP..30.1924I. doi:10.1143/jjap.30.1924. ISSN 0021-4922. S2CID 123428785.
  23. ^ Takeuchi, Tetsuya; Sota, Shigetoshi; Katsuragawa, Maki; Komori, Miho; Takeuchi, Hideo; Amano, Hiroshi; Akasaki, Isamu (April 1, 1997). "Quantum-Confined Stark Effect due to Piezoelectric Fields in GaInN Strained Quantum Wells". Japanese Journal of Applied Physics. Japan Society of Applied Physics. 36 (Part 2, No. 4A): L382–L385. Bibcode:1997JaJAP..36L.382T. doi:10.1143/jjap.36.l382. ISSN 0021-4922. S2CID 95930600.
  24. ^ Takeuchi, Tetsuya; Amano, Hiroshi; Akasaki, Isamu (February 15, 2000). "Theoretical Study of Orientation Dependence of Piezoelectric Effects in Wurtzite Strained GaInN/GaN Heterostructures and Quantum Wells". Japanese Journal of Applied Physics. Japan Society of Applied Physics. 39 (Part 1, No. 2A): 413–416. Bibcode:2000JaJAP..39..413T. doi:10.1143/jjap.39.413. ISSN 0021-4922. S2CID 121954273.
  25. ^ "Nagoya University profile 2008" (PDF). Archived from the original (PDF) on October 17, 2012.
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  29. ^ "NEC: News Release 98/11/04-01". Retrieved November 10, 2015.
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  32. ^ [1] Archived December 13, 2012, at the Wayback Machine
  33. ^ "Fellow Class of 1999". Archived from the original on December 26, 2012. Retrieved February 23, 2013.
  34. ^ "ECS SSS&T Award". Archived from the original on October 12, 2014. Retrieved November 10, 2015.
  35. ^ "Toray Science and Technology Prize : List of Winners". Retrieved November 10, 2015.
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  38. ^ "Social/Economic Well-Being : Technical Achievement: The Development of Blue Light Emitting Semiconductor Devices - Development of the blue light emitting diode and laser diode is the final link in completing the light spectrum for semiconductor devices". Retrieved November 10, 2015.
  39. ^ "IAP - About IAP". Retrieved November 10, 2015.
  40. ^ "Recipient: 2006 John Bardeen Award". Archived from the original on March 4, 2016. Retrieved November 10, 2015.
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  42. ^ "INAMORI FOUNDATION". Archived from the original on March 4, 2016. Retrieved November 10, 2015.
  43. ^ "トピックス / 赤﨑勇・名城大学大学院理工学研究科教授および名古屋大学特別教授へ知的財産特別貢献賞を授与" [Topics / Special Award for Intellectual Property Activities goes to Prof. Isamu Akasaki]. JST (in Japanese). September 13, 2011. Retrieved April 8, 2011.
  44. ^ "Chanda Kochhar among three Indians get Asia Game Changer awards". The Economic Times. September 16, 2015. Archived from the original on September 21, 2015. Retrieved October 28, 2020.
  45. ^ "Fifth UNESCO Medals for contributions to the development of nanoscience and nanotechnologies ceremony". UNESCO. February 2016. Retrieved April 3, 2021.
  46. ^ "Types of Medals".
  47. ^ "Orders of the Rising Sun". Retrieved November 10, 2015.
  48. ^ "Order of Culture". Retrieved November 10, 2015.
  49. ^ "Novelist, LED developer awarded". Archived from the original on April 11, 2013. Retrieved March 1, 2013.
  50. ^ "M͎͎". Archived from the original on September 13, 2016. Retrieved November 10, 2015.

Further reading