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.

[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".

[10][11] His elder brother is Masanori Akazaki [ja] who was an electronic engineering researcher and a Professor Emeritus at Kyushu University.

[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.

[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.

From 1996 he started as a Project Leader of "High-Tech Research Center for Nitride Semiconductors" at Meijo University, sponsored by MEXT until 2004.