Nick Holonyak and the first practical visible LED
A coal-miner’s son helped change how the world makes light.
At fifteen, Nick Holonyak Jr. helped repair flood damage on the Illinois Central Railroad, working for thirty hours during one exhausting stint. The experience strengthened his resolve to continue his education rather than spend his life in heavy manual labour.
He went on to earn three degrees in electrical engineering at the University of Illinois, completing his doctorate in 1954 under John Bardeen, a co-inventor of the transistor.
A different kind of light
By 1962, Holonyak was working at General Electric’s semiconductor laboratory in Syracuse, New York. While other researchers concentrated on infrared radiation, invisible to the human eye, he wanted to make a semiconductor emit visible light.
He worked with gallium arsenide phosphide, an alloy whose composition could be adjusted to change the light it produced. Growing suitable crystals was difficult, and some colleagues doubted his approach. Holonyak persisted.
In 1962, he developed the first practical visible-spectrum light-emitting diode, or LED. It glowed red when an electric current passed through it.
The device offered a way to produce visible light directly within a semiconductor, rather than by heating a filament. Holonyak believed LEDs would eventually replace incandescent bulbs. At the time, the distance between a small red light and a lamp bright enough to illuminate a room seemed enormous.
From a red glow to everyday light
Closing that gap took decades of work by many researchers. Red LEDs were an important beginning, but they could not provide the white light needed for everyday lighting on their own. Efficient blue LEDs remained a formidable challenge.
In the early 1990s, Isamu Akasaki, Hiroshi Amano and Shuji Nakamura achieved the blue-light breakthrough. Their work made bright, energy-efficient white LED lighting possible and earned them the 2014 Nobel Prize in Physics.
The lamps now lighting our homes and streets were therefore not the achievement of one inventor. Holonyak’s red LED was an early milestone in a much longer collective effort. His prediction nevertheless proved farsighted: LEDs became a practical alternative to the incandescent bulb.
The work he passed on
In 1963, Holonyak returned to the University of Illinois, where he combined research with teaching for fifty years before retiring in 2013. His laboratory continued to develop semiconductor technology, often through work undertaken with his students.
The Lemelson-MIT programme credits him with advising sixty graduate students, many of whom became leaders in their field. In 1977, he and his student Edward Rezek developed the first quantum-well semiconductor laser, an advance important to optical communications.
Holonyak died in 2022, aged ninety-three. His invention had helped change how the world makes light. His teaching ensured that the work would continue in other hands.
Beyond lighting: new uses for LEDs
LEDs do more than illuminate rooms. Their small size and precise electronic control have opened possibilities in communication and display technology, while adjustable lighting is helping researchers explore how light affects our daily rhythms.
Data through light
Li-Fi uses rapidly modulated light to transmit data wirelessly. The changes are too fast for the eye to notice, and a receiver converts them into digital information. Because the optical link does not use radio frequencies, it offers an alternative where radio interference is a concern. It has limits, however: light does not pass through opaque walls, and obstructions can disrupt the connection. Li-Fi is therefore better described as a complement to Wi-Fi than a universal replacement.
Smaller LEDs, sharper displays
MicroLED displays use microscopic LEDs to produce their own light, without a separate backlight. Their brightness makes them promising for displays that need to remain clear in strong ambient light, including augmented-reality devices. But making very small LEDs efficiently and assembling them into reliable displays remain difficult engineering challenges.
Light and our daily rhythms
Adjustable LED lighting can change in brightness and spectrum throughout the day. This matters because light helps regulate the body’s internal clock. Guidance from the International Commission on Illumination recommends substantial daytime light exposure, much lower levels before bedtime, and near-darkness during sleep. The aim is not simply to imitate sunrise and sunset, but to provide appropriate light at the appropriate time.