From Holonyak to Today

The demonstration of direct bandgap alloy semiconductor (GaAsP) visible (red) emitters by Nick Holonyak at General Electric in 1962 began the evolution of high-brightness LED technology. Today, high-brightness LEDs are a growing $12 billion business with applications which include traffic signals, automobiles, camera flash, display backlighting, and general illumination. This paper will discuss the key developments which enabled the evolution from the early red device with performance of less than 0.1 lumen/watt (lm/W) to today's devices with performance in excess of 100 lm/W. LEDs are now replacing conventional light sources for general lighting applications. By 2020, LEDs are expected to be the dominant technology for general illumination; the energy savings will be around 10% of the total electricity utilized, which is the equivalent of 50 large nuclear power plants for the United States alone.