InGaN Red LED Quantum Wells for Wavelength Stability at High Current

The patent changes the compositional parameters of the quantum well by increasing indium concentration to greater than 18% mole fraction and optimizing the thickness of InGaN layers and GaN barrier layers. This parameter optimization allows the LED to maintain stable red wavelength (>605 nm) even at high current densities (≥2 A/cm2) where conventional LEDs exhibit wavelength shift and spectrum broadening, while simultaneously achieving high wall plug efficiency

The patent employs a composite material structure consisting of multiple quantum wells with alternating InGaN active layers and GaN barrier layers. This composite structure, with specific thickness ratios and indium concentrations, enables the device to achieve both high efficiency operation and stable wavelength emission by distributing strain and optimizing carrier confinement across the composite quantum well structure

The patent optimizes the indium concentration parameter to greater than 18% mole fraction in the InGaN quantum well, which shifts the emission to longer red wavelengths (>605 nm). Simultaneously, the patent optimizes the thickness parameters of both the InGaN active layers and GaN barrier layers to minimize strain and reduce non-radiative recombination, thereby maintaining high internal quantum efficiency despite the high indium content

The patent applies local quality optimization by creating a structured composition within the quantum well, with specific InGaN layers having different thicknesses and indium concentrations, separated by GaN barrier layers. This local variation in composition allows different regions to contribute differently to the overall performance, with high indium regions providing long wavelength emission and optimized barrier regions maintaining efficiency by reducing defect-related non-radiative recombination