Why It Was Almost Impossible to Make the Blue LED

08 Feb 2024 (9 months ago)

History of LEDs

The first visible LED was created in 1962 by Nick Holonyak, but it was only red.
For decades, only red and green LEDs were available, limiting their use to indicators, calculators, and watches.
The blue LED was challenging to create, and despite efforts from major electronics companies, it remained elusive for over 30 years.
Shūji Nakamura, a researcher at a small Japanese chemical company named Nichia, defied the industry and made three radical breakthroughs to create the world's first blue LED.
Nakamura's success was due to his persistence and the support of Nichia's founder, Nobuo Ogawa, who invested in his moonshot project.

LEDs get their color from the electronics themselves, not the plastic covers.
LEDs work by allowing electrons to jump from the valence band to the conduction band, releasing energy as photons of light.
The size of the band gap determines the color of the light emitted by an LED.

Nakamura's initial proposal to Ogawa involved mastering MOCVD (Metal Organic Chemical Vapor Deposition) in Florida to create high-quality crystal for blue LEDs.
After returning to Japan, Nakamura focused on gallium nitride despite its challenges, including difficulties in crystal growth and p-type doping, while most researchers favored zinc selenide.
Nakamura's breakthrough came when he developed the two-flow MOCVD reactor, which improved the quality of gallium nitride crystals by preventing the formation of powdery waste.
He created the world's first p-type gallium nitride by heating magnesium-doped gallium nitride to 400 degrees Celsius, a process known as annealing.
Nakamura created an indium gallium nitride crystal by adjusting his MOCVD reactor to pump as much indium as he could onto the gallium nitride.
Nakamura fixed the issue of electron overflow by creating a "hill" structure in the LED.

Nichia called a press conference in Tokyo to announce the world's first true blue LED, which had a light output power of 1,500 microwatts and emitted a perfect blue at exactly 450 nanometers.
Nichia's revenue nearly doubled within three years of introducing the blue LED, and they made the jump from blue to white by placing a yellow phosphor over the LED.
Nakamura left Nichia in 2000 after more than 20 years at the company and began consulting for Cree, another LED company.
Nichia sued Nakamura for leaking company secrets, and Nakamura counter-sued Nichia for never properly compensating him for his invention.
The Japanese courts ruled in Nakamura's favor and ordered Nichia to pay him 10 times his initial request, but Nichia appealed and the case was eventually settled with a payout of $8 million, which only covered Nakamura's legal fees.

Blue LEDs are now used in various applications, including house lights, streetlights, traffic lights, and displays.
LED bulbs are more efficient, last longer, are safer to handle, and are completely customizable compared to incandescent or fluorescent bulbs.
The price of LED bulbs has come down to only a couple of dollars more than other types of bulbs, and they can recoup their cost in only two months with average daily use and electricity pricing.
LED lighting has revolutionized the lighting industry, with over half of residential lighting sales in the world being LED in 2022.

Shuji Nakamura, the inventor of the blue LED, is now working on the next generation of LEDs, micro LEDs, and UV LEDs.
Micro LEDs can be used for near-eye displays such as AR and VR.
UV LEDs could be used to sterilize surfaces and kill pathogens.
Nakamura is also interested in nuclear fusion and has started a company to develop nuclear fusion technology.

Nakamura was awarded the Nobel Prize in physics in 2014 for his work on the blue LED.
Nakamura's determination, critical thinking, and problem-solving skills set him apart from other researchers working on the blue LED.