Newswise — WASHINGTON D.C., October 7, 2014 -- The 2014 Nobel Prize in Physics was jointly awarded to Isamu Akasaki of Mejio University and Nagoya University, Hiroshi Amano of Nagoya University and Shuji Nakamura of University of California, Santa Barbara “for the invention of efficient blue light-emitting diodes, which has enabled bright and energy-saving white light sources.”
To help journalists and the public understand the context of this work, AIP is compiling a Physics Nobel Prize Resources page featuring relevant scientific papers and articles, quotes from experts and other resources. Relevant papers published by AIP Publishing will be made freely available thru December 31, 2014. The page will be updated throughout the day and can be accessed at: http://www.aip.org/science-news/nobel/physics2014.
Overview
The 2014 Nobel Prize in Physics honors scientists Isamu Akasaki, Hiroshi Amano and Shuji Nakamura for the invention of the blue light-emitting diode (LED), a breakthrough in technology that has revolutionized electronic displays and residential and commercial lighting.
LEDs are made from layers of semiconductors, materials that act like a cross between a conductor and an insulator, and whose electrical properties can be controlled with the addition of impurities called dopants. Light is emitted from LEDs when a current is applied, driving excess electrons for one layer (the n-layer) to recombine with positive “holes” from another layer (the p-layer). The wavelength of this light depends on the material properties of the semiconductors.
Scientists’ understanding of the fundamental physics of semiconductors progressed rapidly in the 1940s, which led to numerous applications including LEDs -- the first of which were created in the 1950s, ‘60s, and ‘70s, but emitted visible light only from the red to green part of the spectrum. Blue and ultraviolet LEDs remained stubbornly difficult to manufacture for more than three decades.
Akasaki, Amano and Nakamura chose gallium nitride as the main component for blue light LEDs, even though the material was notoriously difficult to work with. Researchers had struggled for years to grow high-quality gallium nitride crystals and repeatedly failed to create a p-type layer.
Yet through thousands of experiments the three 2014 Nobel laureates persisted. Working together, Akasaki and Amano succeeded in growing high-quality gallium nitride crystal on top of an aluminum nitride layer on a sapphire substrate. Nakamura developed an alternate method, growing a thin layer of gallium nitride at a low temperature before growing subsequent layers at a higher temperature. The three researchers also developed novel ways to create p-layers.
The introduction of blue LEDs in the 1990s provided the missing piece for the widespread adoption of the new lighting technology. Blue LEDs have been used to create white light by combining them with other materials known as phosphors -- or by mixing their light with the light from red and green LEDs.
This type of lighting now illuminates homes, offices and streets. It enables the backlight displays on cell phones, tablets, computers and TVs. And it does so greenly -- LEDs are very long lasting and highly energy efficient, saving precious resources as the human population and its demands for artificial light continue to grow.
Statement from AIP Executive Director and CEO H. Fredrick Dylla
"The blue LED is a fundamental invention that is rapidly changing the way we bring light to every corner of the home, the street and the workplace -- a practical invention that comes from a fundamental understanding of physics in the solid state," said H. Frederick Dylla, the executive director and CEO of the American Institute of Physics.
"With the International Year of Light in 2015, the world will be celebrating LEDs and their efficient, commercial applications for general lighting, high-tech research and life-saving medicines," he added.
Statement for AIP Publishing CEO John Haynes
"The rich history of LEDs has been chronicled in AIP Publishing journals since the discovery of red LEDs by Nick Holonyak appeared in Applied Physics Letters in 1962," said John Haynes, CEO of AIP Publishing LLC. "Today we celebrate the Nobel Prize committee's recognition of blue LEDs by making a selection of articles related to those discoveries freely available to the public."
Seminal Papers from AIP Publishing
Free Access thru December 31, 2014Novel metalorganic chemical vapor deposition system for GaN growthShuji Nakamura, Yasuhiro Harada and Masayuki SenoAppl. Phys. Lett. 58 , 2021 (1991)
High‐power InGaN/GaN double‐heterostructure violet light emitting diodesShuji Nakamura, Masayuki Senoh and Takashi MukaiAppl. Phys. Lett. 62 , 2390 (1993)
In x Ga(1−x)N/In y Ga(1−y)N superlattices grown on GaN filmsShuji Nakamura, Takashi Mukai, Masayuki Senoh, Shin‐ichi Nagahama and Naruhito IwasaJ. Appl. Phys. 74 , 3911 (1993)
Candela‐class high‐brightness InGaN/AlGaN double‐heterostructure blue‐light‐emitting diodesShuji Nakamura, Takashi Mukai and Masayuki SenohAppl. Phys. Lett. 64 , 1687 (1994)
High‐brightness InGaN/AlGaN double‐heterostructure blue‐green‐light‐emitting diodesShuji Nakamura, Takashi Mukai and Masayuki SenohJ. Appl. Phys. 76 , 8189 (1994)
InGaN/AlGaN blue‐light‐emitting diodesShuji NakamuraJ. Vac. Sci. Technol. A 13 , 705 (1995)
75 Å GaN channel modulation doped field effect transistorsJinwook Burm, William J. Schaff, Lester F. Eastman, Hiroshi Amano and Isamu AkasakiAppl. Phys. Lett. 68 , 2849 (1996)
Optical gain and carrier lifetime of InGaN multi‐quantum well structure laser diodesShuji Nakamura, Masayuki Senoh, Shin‐ichi Nagahama, Naruhito Iwasa, Takao Yamada, Toshio Matsushita, Yasunobu Sugimoto and Hiroyuki KiyokuAppl. Phys. Lett. 69 , 1568 (1996)
Continuous‐wave operation of InGaN multi‐quantum‐well‐structure laser diodes at 233 KShuji Nakamura, Masayuki Senoh, Shin‐ichi Nagahama, Naruhito Iwasa, Takao Yamada, Toshio Matsushita, Yasunobu Sugimoto and Hiroyuki KiyokuAppl. Phys. Lett. 69 , 3034 (1996)
Room‐temperature continuous‐wave operation of InGaN multi‐quantum‐well structure laser diodesShuji Nakamura, Masayuki Senoh, Shin‐ichi Nagahama, Naruhito Iwasa, Takao Yamada, Toshio Matsushita, Yasunobu Sugimoto and Hiroyuki KiyokuAppl. Phys. Lett. 69 , 4056 (1996)
Room-temperature continuous-wave operation of InGaN multi-quantum-well-structure laser diodes with a long lifetimeShuji Nakamura, Masayuki Senoh, Shin-ichi Nagahama, Naruhito Iwasa, Takao Yamada, Toshio Matsushita, Yasunobu Sugimoto and Hiroyuki KiyokuAppl. Phys. Lett. 70 , 868 (1997)
Room-temperature continuous-wave operation of InGaN multi-quantum-well structure laser diodes with a lifetime of 27 hoursShuji Nakamura, Masayuki Senoh, Shin-ichi Nagahama, Naruhito Iwasa, Takao Yamada, Toshio Matsushita, Yasunobu Sugimoto and Hiroyuki KiyokuAppl. Phys. Lett. 70 , 1417 (1997)
Continuous-wave operation of InGaN/GaN/AlGaN-based laser diodes grown on GaN substratesShuji Nakamura, Masayuki Senoh, Shin-ichi Nagahama, Naruhito Iwasa, Takao Yamada, Toshio Matsushita, Hiroyuki Kiyoku, Yasunobu Sugimoto, Tokuya Kozaki, Hitoshi Umemoto, Masahiko Sano and Kazuyuki ChochoAppl. Phys. Lett. 72 , 2014 (1998)
Structural properties of InN on GaN grown by metalorganic vapor-phase epitaxyShigeo Yamaguchi, Michihiko Kariya, Shugo Nitta, Tetsuya Takeuchi, Christian Wetzel, Hiroshi Amano and Isamu AkasakiJ. Appl. Phys. 85 , 7682 (1999) Anomalous features in the optical properties of Al1−xInxN on GaN grown by metal organic vapor phase epitaxyShigeo Yamaguchi, Michihiko Kariya, Shugo Nitta, Tetsuya Takeuchi, Christian Wetzel, Hiroshi Amano and Isamu AkasakiAppl. Phys. Lett. 76 , 876 (2000)
Control of strain in GaN by a combination of H2 and N2 carrier gasesShigeo Yamaguchi, Michihiko Kariya, Masayoshi Kosaki, Yohei Yukawa, Shugo Nitta, Hiroshi Amano and Isamu AkasakiJ. Appl. Phys. 89 , 7820 (2001)
Electrical properties of strained AlN/GaN superlattices on GaN grown by metalorganic vapor phase epitaxyShigeo Yamaguchi, Yasuo Iwamura, Yasuhiro Watanabe, Masayoshi Kosaki, Yohei Yukawa, Shugo Nitta, Satoshi Kamiyama, Hiroshi Amano and Isamu AkasakiAppl. Phys. Lett. 80 , 802 (2002)
Laser lift-off technique for freestanding GaN substrate using an In droplet formed by thermal decomposition of GaInN and its application to light-emitting diodesDaisuke Iida, Syunsuke Kawai, Nobuaki Ema, Takayoshi Tsuchiya, Motoaki Iwaya, Tetsuya Takeuchi, Satoshi Kamiyama and Isamu AkasakiAppl. Phys. Lett. 105 , 072101 (2014)
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