A few days ago, the British Micro LED company Plessey issued a press release saying that it had announced the development of the world's first silicon-based InGaN red LED.
Although both InGaN-based blue and green LEDs have been commercially produced, red LEDs are typically based on AlInGaP materials or color-converted red light. For AR applications, due to the severe edge effects of AlInGaP materials and the cavity loss caused by the color conversion process, achieving highly efficient ultra-small pitch red pixels (<5 μm) is still out of reach.
Compared with existing AlInGaP-based red light, InGaN-based red light has a lower manufacturing cost, can be expanded to larger 200 mm or 300 mm wafers, and has a better heat / cool coefficient, so it has a great Appeal. However, due to the high indium content, significant strain is induced in the active region, which reduces the crystal quality and creates many defects. Therefore, using InGaN materials to achieve red spectral emission is challenging. Plessey successfully overcomes these challenges by using a proprietary strain-designed active area to manufacture an efficient InGaN Red LED.
Plessey's InGaN Red Micro LED has a wavelength of 630 nm at 10 A / cm2, a full width at half maximum of 50 nm, a thermal cooling coefficient of more than 90%, and its ultra-small pixel pitch has higher efficiency than traditional AlInGaP and color Converted red light. With this result, Plessey can now make natural blue, green, and red InGaN materials, or use its GaN-on-Silicon platform to tune wavelengths from 400 to 650 nm.