Abstract: GaN-based blue-light-emiting diodes, one of the most important applications with the GaNmaterial that we investigate, are the key color display devices. This paper introduces briefly the material characteristics of GaN, the reason GaN is suitable for blue LEDs and the typical devices which have been invented. It discusses the up-to-date GaN-based LEDs and their working mechanism in detail. From the development of blue LEDs, we can realize that luminescent spectrum and quantum efficiency are improved dramatically by changing device structures, improving material qualities or using new type material. Furthermore, some pivotal technology(including P-doping, annealing temperature, ohmic contact, etc.) in fabrications and the up-to-date state of arts for blue LEDs is discussed throughly too. Finally, the application and prospect in future about GaN based LEDs are forecasted.

Key words: GaN, blue LED, developement