Abstract: 2014 Nobel Prize in physics was awarded jointly to three scientists for the invention of efficient blue light- emitting diodes,which leads a revolution of solid state lighting. Now LED is illuminating the world and benefiting of the mankind. This paper traced the evolution of blue LED from the earliest Ga N growth,and reviews the important historic achievement of LED development. III- nitrides are direct band- gap semiconductors,with its emission wavelength covering the whole spectrum from ultraviolet,visible to infrared. They are ideal material to fabricate optoelectronic devices. And because of exceptional physical properties,they are also suitable for application in high- speed and high- power electronic devices.

Key words: GaN, light-emitting diode, solid state lighting