GaN-Based Light Emitting Diodes

Pujii,T, Gao, Y, Sharma, R., Hu, E. L., DenBaars, S. P. and Nakamura, S. (2004) Increase in the Extraction Efficiency of GaN-based Light-emitting Diodes via Surface Roughening. Appl. Phys. Lett., 84,855. 

The industrial application of SiC began with the blue light emitting diode (LED), which was very weak due to the indirect bandgap of SiC but was the only commercial blue electroluminescent light source at the time (the late 1980s). The SiC blue LED was soon surpassed in intensity by the gallium nitride (GaN)-based... 

K.D. (2007) Enhanced light extraction from GaN-based green light-emitting diode with photonic crystal Appl. Phys. Lett. 91 181109. 

GaN is a wide band gap semiconductor (Eg = 3.4 eV) of considerable technological interest. Light-emitting diodes (LEDs) and laser diodes based on GaN and its alloys of either In or A1 have been successfully commercialized for some time. GaN remains a topic of intense interest, and current research primarily focuses on creating more efficient green and red LEDs and laser diodes for solid state lighting and other applications. 

Kim JS, Kang, JY Jeon PE, Choi JC, Park HL, Kim TW (2004) GaN-based white-light-emitting diodes fabricated with a mixture of Ba3MgSi20g Eu and Sr2Si04 Eu phosphors. Jpn J Appl Phys 43 989... 

Schottky diodes can be manufactured using boron-doped material, and some of these emit a feeble blue luminescence when forward or reverse biased (66). However, the intensity of the luminescence is much lower than that obtainable with SiC blue light-emitting diodes and many orders of magnitude weaker than the recently developed LEDs based on GaN (67). Unlike diamond or SiC, GaN is a direct-gap semiconductor, and the conversion of electrical power to light is very much more efficient. It may be possible to obtain green injection luminescence from a boron-doped diode structure, but this will not compete, in performance or price, with the commercial LEDs based on GaP. 

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