Semiconductor Light-Emitting Device with Segmented Extraction Surface
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Solution Overview
Problem
Conventional light-emitting diodes experience decreased light-emitting efficiency due to non-radiative recombination caused by lattice dislocations on the side walls of the epitaxial structure, especially when the device volume is reduced, leading to inefficient light extraction.
Innovation Solution
A semiconductor light-emitting device with an epitaxial structure comprising a first and second semiconductor stack and an active layer, featuring a main light-extraction surface with specific regions and a reflective stack to enhance light extraction efficiency, where the upper surface is roughened to improve light penetration and reflection, and the electrical current is managed to minimize non-radiative recombination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the volume of the light-emitting diode is decreased, then the device size is reduced, but the light-emitting efficiency is decreased due to increased influence of non-radiative recombination from lattice dislocations on the side wall
Solution Approach 1:
The light-extraction surface is segmented into multiple regions with different light-extraction characteristics. The first light-extraction region has high near-field luminous intensity (70%-100% of maximum) while the second light-extraction region has lower intensity (0%-70% of maximum), with an area ratio between 0.25 and 0.45. This segmentation allows optimized light extraction without increasing device volume.
Solution Approach 2:
Different regions of the light-extraction surface are given different local properties. The first light-extraction region is designed with specific characteristics (higher luminous intensity) to maximize light extraction where needed, while the second region has different properties, creating non-uniform local quality that improves overall efficiency without requiring larger device volume.
2Volume of moving object
If the device volume is decreased, then the device size is reduced, but the influence of non-radiative recombination from lattice dislocations on the side wall becomes more obvious
Solution Approach 1:
The patent extracts and addresses the harmful side-wall effects by designing a specific light-extraction surface configuration. By creating regions with optimized light extraction properties, the harmful non-radiative recombination at the side wall is compensated for, allowing small device volume without proportionally increased harmful effects.
Solution Approach 2:
The patent converts the challenge of side-wall effects in miniaturized devices into a benefit by designing a non-uniform light-extraction surface. The specific regional distribution of light extraction properties transforms the potential harm of increased side-wall influence into an opportunity for optimized light extraction efficiency in compact devices.
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
The solution significantly enhances light-emitting efficiency by optimizing the light-extraction surface and current distribution, reducing non-radiative recombination and increasing the percentage of electrical current flowing through the epitaxial structure, thereby improving the overall light output.
Implementation Method 1
the upper surface is roughened to improve light penetration and reflection
Implementation Method 2
the upper surface is roughened to improve light penetration and reflection
Implementation Method 3
electrical holes and electrons recombine in the active layer 10b to release light
Data Source
AI summary
A semiconductor light-emitting device comprises an epitaxial structure comprising a first semiconductor stack, a second semiconductor stack, and an active layer between the first semiconductor stack and second semiconductor stack for emitting a light; and a main light-extraction surface on the first semiconductor stack, wherein the light passes through the main light-extraction surface. The main light-extraction surface comprises a first light-extraction region, a second light-extraction region, and a maximum near-field luminous intensity. The distribution of the near-field luminous intensity in the first light-extraction region is between 70% and 100% of the maximum near-field luminous intensity, the distribution of the near-field luminous intensity in the second light-extraction region is between 0% and 70% of the maximum near-field luminous intensity. A ratio of an area of the first light-extraction region to an area of the second light-extraction region is between 0.25 and 0.45.