Achieving InGaN-Based Red Light-Emitting Diodes by Increasing the Growth Pressure of Quantum Wells

We extended the emission wavelength of indium gallium nitride (InGaN) quantum wells to the yellow–red region by utilizing increased growth pressure. A clear 54-nm redshift of the peak wavelength was observed that corresponded to the increase in quantum well growth pressure from 200 to 550 Torr. The 4-inch red epi-wafer presented uniform emission with a standard deviation of 3.3 nm. The packaged red LED exhibited the highest wall-plug efficiency of 4.92% and an external quantum efficiency of 5.11% at 0.5 A/cm2 with a peak wavelength at 619 nm. The minimum full width at half maximum of the red LED was around 50 nm, which contributed to the high color purity of the emission in the red region. These results suggest significant progress in developing high-efficiency InGaN red LEDs using the high-pressure epitaxial growth method.