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

摘要

InGaN red light emitting diode (LED) is one of the crucial bottlenecks thatmust be broken through to realize high-resolution full-color mini/micro-LEDdisplays. The efficiency of InGaN LEDs drops rapidly as the emission spectrago from blue/green to red range due to the poor quality of high-indium-contentInGaN materials. Here, high-performance InGaN red LEDs on sapphiregrown by metal–organic chemical vapor deposition through strain modulationare reported. A composite buffer layer is proposed to increase the surfacelattice constant of GaN and hence successfully enhances the indium incorporationefficiency of the following InGaN active layers. Consequently, a highefficiencyInGaN red mini-LED chip (mesa area: 100 × 200 μm~2) with a peakwavelength 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 ofRec.2020 color gamut by using the InGaN red mini-LED chips is fabricated.The study signifies the great potentials of full-nitrides high-resolution fullcolormini/micro-LED displays.