LED epitaxial structure and manufacturing method therefor, light emitting device and display panel
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Solution Overview
Problem
The luminous efficiency of LEDs is low due to factors such as light absorption by the GaAs substrate and critical angle loss of total reflection, which affects light extraction and conversion efficiency.
Innovation Solution
An LED epitaxial structure is designed with a substrate, N-type and P-type confinement layers, and an active layer comprising alternately disposed quantum well and barrier layers, where a second quantum barrier layer with greater thickness is positioned between two first quantum barrier layers to enhance carrier blocking and light conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional quantum well and barrier layers are used with uniform thickness, then the structure is simple and easy to manufacture, but the luminous efficiency is low due to insufficient light conversion efficiency and carrier blocking
Solution Approach 1:
The patent applies local quality by varying the thickness of quantum barrier layers within the active layer structure. Specifically, at least one quantum barrier layer has a different thickness from the others, creating localized differences in carrier blocking capability and light conversion efficiency. This allows optimization of luminous efficiency in specific regions without complicating the overall manufacturing process, as the thickness variation can be achieved through standard MOCVD deposition by adjusting deposition parameters for specific layers.
2Loss of energy
If the number of quantum well pairs is increased to improve light conversion efficiency, then the active layer thickness increases and carrier diffusion length is exceeded, but if the number is kept low then light conversion efficiency remains insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the thickness parameter of quantum barrier layers rather than simply increasing the number of quantum well pairs. By adjusting the thickness of at least one quantum barrier layer to be different from the others, the patent optimizes carrier blocking and light conversion efficiency within the existing active layer thickness, avoiding the problem of exceeding carrier diffusion length while still achieving improved light conversion efficiency.
3Manufacturing precision
If GaAs substrate is used for LED growth, then high-quality lattice-matched AlGaInP quantum well epitaxial layer can be prepared, but light absorption by the GaAs substrate reduces light extraction efficiency
Solution Approach 1:
The patent applies the blessing in disguise principle by designing the quantum barrier layer thickness variation to compensate for the GaAs substrate's light absorption. The optimized barrier layer structure improves carrier blocking and light conversion efficiency, which indirectly mitigates the impact of substrate absorption by maximizing the light generated within the active layer, thereby converting the limitation of substrate absorption into an opportunity to optimize the epitaxial structure itself.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration increases the number of quantum well pairs within the carrier diffusion length, improves light conversion efficiency, and enhances the luminous efficiency of LEDs, addressing the issue of low luminous efficiency in existing LEDs.
Implementation Method 1
the active layer includes quantum well layers and quantum barrier layers, which are alternately disposed
Implementation Method 2
a thickness of the second quantum barrier layers is greater than a thickness of the first quantum barrier layers
Data Source
AI summary
The present disclosure relates to an LED epitaxial structure and a manufacturing method therefor, a light emitting device and a display panel. The LED epitaxial structure includes: a substrate, an N-type confinement layer, an active layer and a P-type confinement layer, which are disposed in sequence from bottom to top, wherein the active layer includes quantum well layers and quantum barrier layers, which are alternately disposed, a part of the quantum barrier layers are first quantum barrier layers, at least one of the quantum barrier layers is a second quantum barrier layer, the second quantum barrier layer is located between two first quantum barrier layers, and a thickness of the second quantum barrier layers is greater than a thickness of the first quantum barrier layers.