The phenomenon of electroluminescence was discovered in 1907 using silicon carbide and the first commercial LEDs were based on SiC. Yellow LEDs made from 3C-SiC were manufactured in the Soviet Union in the 1970s and blue LEDs (6H-SiC) worldwide in the 1980s.
Carbide LED production soon stopped when a different material, gallium nitride, showed 10–100 times brighter emission. This difference in efficiency is due to the unfavorable indirect bandgap of SiC, whereas GaN has a direct bandgap which favors light emission. However, SiC is still one of the important LED components: It is a popular substrate for growing GaN devices, and it also serves as a heat spreader in high-power LEDs.