A South Korean company has developed a technology that can be used to make red LEDs by developing gallium nitride (GaN) on a sapphire wafer substrate. It will be interesting to see whether the development can be a steppingstone for improvement in reliability and durability of red LED.
Soft-EPi announced on Monday that it has succeeded in making red LEDs using GaN. The company explained that it used a same method for making blue and green LEDs where GaN is developed on a sapphire substrate.
According to the company, most of red LEDs are currently made through aluminum gallium indium phosphide (AlGaInP) or a fluorescent substance. However, red LEDs based on AlGaInP are very expensive and tend to lose their effectiveness as they become smaller.
On the other hand, red LEDs based on GaN are relatively cost effective and have excellent mechanical strength and highly reliable. However, there has yet to be any company that has successfully developed red LED based on GaN until Soft-EPi. Although there were cases when red LEDs were developed through special techniques such as ‘nano-rod’, none of the developments came close to mass-production.

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<Red light emitting from a sapphire substrate where gallium nitrite is developed (Source: Soft-EPi)>

“GaN-based red LED requires advanced techniques such as injecting indium into active layer and increased current density causing short wavelength.” said a representative from Soft-EPi.
The company emphasized that its technique overcomes many existing limitations.
“Our technology has been developed through stress control technique and highly-concentrated indium injection technology.” said CEO Hwang Seong-min of Soft-EPi. “Our technology also allows MOCVD (metal organic chemical vapor deposition) production lines that are used for blue and green LEDs to be used for red LEDs as well.”
It will be interesting to see whether the company’s technology can also be utilized for microLEDs as well. microLED is an ultra-small LED that is smaller than 100 micrometers. Red LEDs lose their performance as they become smaller. Soft-EPi’s goal is to develop red LEDs that can be utilized for next-generation displays. It plans to cooperate with domestic and foreign companies and institutions and commercialize GaN-based red LEDs.
Staff Reporter Yun, Geonil | benyun@etnews.com