High‐Efficiency InGaN Red Mini‐LEDs on Sapphire Toward Full‐Color Nitride Displays: Effect of Strain Modulation

InGaN red light emitting diode (LED) is one of the crucial bottlenecks that must be broken through to realize high‐resolution full‐color mini/micro‐LED displays. The efficiency of InGaN LEDs drops rapidly as the emission spectra go from blue/green to red range due to the poor quality of high‐indium‐content InGaN materials. Here, high‐performance InGaN red LEDs on sapphire grown by metal–organic chemical vapor deposition through strain modulation are reported. A composite buffer layer is proposed to increase the surface lattice constant of GaN and hence successfully enhances the indium incorporation efficiency of the following InGaN active layers. Consequently, a high‐efficiency InGaN red mini‐LED chip (mesa area: 100 × 200 µm2) with a peak wavelength of 629 nm and an external quantum efficiency of 7.4% is realized. Finally, a full‐color nitride mini‐LED display panel with 74.1% coverage of Rec.2020 color gamut by using the InGaN red mini‐LED chips is fabricated. The study signifies the great potentials of full‐nitrides high‐resolution full‐color mini/micro‐LED displays. A strain modulation strategy to expanse the surface lattice of the GaN epilayer and thus enhancing the indium incorporation in InGaN multiple quantum wells is proposed. High‐efficiency InGaN red mini‐light emitting diode (LED) chip with external quantum efficiency value up to 7.4% and full‐color nitride mini‐LED display are demonstrated. The results provide a convenient solution to accelerate the development of full‐color mini/micro‐LED displays.