Monolithic Multi-Wavelength LED Structure With Strain-Relieving Layer
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Solution Overview
Problem
The challenge lies in aligning small LEDs with high accuracy on a driving substrate for high-resolution color displays, as existing technologies face difficulties in achieving precise alignment and efficient light emission across different wavelengths, particularly in generating red light with high indium composition in 3D light-emitting structures.
Innovation Solution
A monolithic light-emitting device is designed with a base semiconductor layer, a 3D light-emitting structure, and a flat light-emitting structure, where a strain-relieving layer relieves lattice mismatch between the base semiconductor layer and the flat light-emitting structure, allowing for the growth of a GaN-based superlattice layer, and a mask layer with patterns to form 3D and flat light-emitting structures that generate blue, green, and red light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the size of LEDs is reduced to achieve high resolution, then the resolution of color displays is improved, but the alignment accuracy of LEDs on driving substrate deteriorates
Solution Approach 1:
The patent combines multiple light-emitting structures (3D light-emitting structures with different indium compositions) into a single integrated device on one driving substrate. This merging approach eliminates the need for separate alignment of multiple discrete LEDs, thereby maintaining high resolution while avoiding alignment accuracy issues that would arise from reducing individual LED sizes.
2Speed
If indium composition is increased in light-emitting structure to generate red light, then the wavelength of emitted light is improved, but the lattice mismatch between layers increases
Solution Approach 1:
The patent applies local quality by creating 3D light-emitting structures with spatially varying indium compositions. Different regions of the light-emitting structure have different indium concentrations, allowing the generation of multiple wavelengths (blue, green, red) within a single structure while managing lattice mismatch through localized composition control.
Solution Approach 2:
The patent employs composite materials by combining multiple semiconductor layers with different indium compositions (InGaN layers) to form a heterogeneous structure. This composite approach enables the material to emit multiple wavelengths while the superlattice buffer layer manages the lattice mismatch between layers with different compositions.
3Adaptability or versatility
If 3D light-emitting structure is used to generate multi-wavelength light, then the versatility of light emission is improved, but the internal quantum efficiency deteriorates due to lattice mismatch
Solution Approach 1:
The patent introduces a superlattice buffer layer as an intermediary between the driving substrate and the 3D light-emitting structures. This intermediate layer serves as a transition zone that reduces lattice mismatch and dislocation density, thereby maintaining high internal quantum efficiency while enabling multi-wavelength emission through varying indium compositions in the light-emitting structures.
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 enhances the internal quantum efficiency and color purity of the light-emitting device, enabling high-efficiency multi-wavelength light emission and simplifying the manufacturing process by reducing the need for separate alignment of blue, green, and red light-emitting devices.
Implementation Method 1
a strain-relieving layer formed on the base semiconductor layer in an area of the light-emitting device in which at least the flat light-emitting structure is formed, wherein the strain-relieving layer relieves lattice mismatch between the base semiconductor layer and the flat light-emitting structure
Implementation Method 2
a three-dimensional (3D) light-emitting structure on the base semiconductor layer, the 3D light-emitting structure including at least one semi-polar surface; a flat light-emitting structure on the base semiconductor layer, the flat light-emitting structure including a polar surface, wherein the flat light-emitting structure generates light having a wavelength different from a wavelength of light generated by the 3D light-emitting structure
Data Source
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AI summary
A light-emitting device includes a base semiconductor layer, a three-dimensional (3D) light-emitting structure, and a flat light-emitting structure formed in a flat shape, wherein the flat light-emitting structure generates light having a different wavelength than that of the 3D light-emitting structure. A strain-relieving layer relieving lattice mismatch between the base semiconductor layer and the flat light-emitting structure may be arranged on the base semiconductor layer in an area in which at least the flat light-emitting structure is formed.