In 1961, experimenters Bob Biard and Gary Pittman working at Texas Instruments, found that gallium arsenide gave off infrared radiation when electric current was applied. Biard and Pittman were able to establish the priority of their work and received the patent for the infrared light-emitting diode.

The first practical visible-spectrum (red) LED was developed in 1962 by Nick Holonyak Jr., while working at General Electric Company. He later moved to the University of Illinois at Urbana-Champaign. Holonyak is seen as the "father of the light-emitting diode". M. George Craford, a former graduate student of Holonyak's, invented the first yellow LED and 10x brighter red and red-orange LEDs in 1972. Up to 1968 visible and infrared LEDs were extremely costly, on the order of US $200 per unit, and so had little practical application. The Monsanto Corporation was the first organization to mass-produce visible LEDs, using gallium arsenide phosphide in 1968 to produce red LEDs suitable for indicators. Hewlett Packard (HP) introduced light-emitting diodes in 1968, initially using GaAsP material supplied by Monsanto. The technology proved to have major applications for alphanumeric displays and was integrated into HP’s early handheld calculators.

Practical Uses

The first commercial LEDs were commonly used as replacements forincandescent indicators, and in seven-segment displays, first in expensiveequipment such as laboratory and electronics test equipment, then later insuch appliances as TVs, radios, telephones, calculators, and even watches(see list of signal applications). These red LEDs were bright enough only foruse as indicators, as the light output was not enough to illuminate an area.Later, other colors became widely available and also appeared in appliancesand equipment. As the LED materials technology became more advanced,the light output was increased, while maintaining the efficiency and thereliability to an acceptable level. The invention and development of the highpower white light LED led to use for illumination (see list of illumination applications).

Continuing Development

The first high-brightness blue LED was demonstrated by Shuji Nakamura of Nichia Corporation and wasbased on InGaN borrowing on critical developments in GaN nucleation on sapphire substrates and thedemonstration of p-type doping of GaN which were developed by Isamu Akasaki and H. Amano in Nagoya.In 1995, Alberto Barbieri at the Cardiff University Laboratory (GB) investigated the efficiency and reliabilityof high-brightness LEDs demonstrated a very impressive result by using a transparent contact made of indiumtin oxide (ITO) on (AlGaInP/GaAs) LED. The existence of blue LEDs and high efficiency LEDs quickly ledto the development of the first white LED, which employed a Y3Al5O12:Ce, or "YAG", phosphor coating tomix yellow (down-converted) light with blue to produce light that appears white. Nakamura was awarded the2006 Millennium Technology Prize for his invention.

The development of LED technology has caused their efficiency and light output to increase exponentially,with a doubling occurring about every 36 months since the 1960s, in a similar way to Moore's law. Theadvances are generally attributed to the parallel development of other semiconductor technologies andadvances in optics and material science. This trend is normally called Haitz's Law after Dr. Roland Haitz.