Light Emitting Element Recombination Suppression Structure
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Solution Overview
Problem
As light emitting elements, such as LEDs, are miniaturized, nonradiative recombination at the end surface of the active layer increases, leading to reduced light emission efficiency due to damage, dangling bonds, and impurities, resulting in a larger non-light emission area and lower efficiency.
Innovation Solution
A recombination suppression structure with a bandgap larger than the active layer is provided near the end surface of the light emitting element, typically using a crystallized film or diffusion section to prevent nonradiative recombination, which is formed by materials like AlInP or Al2O3, and is integrated into the manufacturing process to cover the end surface and improve crystal structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the light emitting element is miniaturized to increase arrangement density, then high resolution is achievable, but nonradiative recombination at the end surface increases and light emission efficiency is reduced
Solution Approach 1:
The patent applies local quality by providing a recombination suppression structure specifically at the end surface region of the active layer, where nonradiative recombination occurs most frequently. This structure has different properties (larger bandgap) than the bulk active layer, creating a localized protective zone that suppresses nonradiative recombination at the problematic end surface region while maintaining the original light emission properties of the bulk active layer.
2Productivity
If miniaturization proceeds to increase arrangement density, then high resolution is achievable, but the area ratio of non-light emission section increases leading to lowered light emission efficiency
Solution Approach 1:
The recombination suppression structure is localized at the end surface region, creating a protective zone with different bandgap properties. This allows the bulk of the active layer to maintain its light emission function while the end surface region is protected from nonradiative recombination, thus preserving efficiency even as device size decreases and end surface effects become more significant.
3Loss of energy
If a recombination suppression structure with larger bandgap is provided near the end surface, then nonradiative recombination is suppressed and light emission efficiency is improved, but device structure becomes more complex
Solution Approach 1:
The recombination suppression structure is formed during the manufacturing process before the device is completed and put into service. By preliminarily protecting the end surface region with a structure having larger bandgap, nonradiative recombination is prevented from the outset, improving light emission efficiency without requiring additional complex components or post-processing steps.
Solution Approach 2:
The patent changes the bandgap parameter of the semiconductor structure by introducing a recombination suppression structure with a larger bandgap than the active layer. This parameter change creates an energy barrier that prevents nonradiative recombination at the end surface, improving efficiency while maintaining structural simplicity through a single additional layer rather than complex multi-component systems.
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 suppression of nonradiative recombination at the end surface of the active layer enhances light emission efficiency by widening the light emission region and improving device characteristics, such as optical output, by effectively preventing nonradiative recombination and restoring the end surface during the manufacturing process.
Implementation Method 1
nonradiative recombination at the end surface of the active layer has a greater impact on its light emission efficiency. The nonradiative recombination is a phenomenon in which a carrier generated by bond of a hole and an electron does not emit light, but generates heat.
Implementation Method 2
a recombination suppression structure provided in vicinity of an end surface of the active layer, the recombination suppression structure having a bandgap larger than a bandgap of the active layer
Data Source
AI summary
A light emitting element includes: a laminated body including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer in this order, the second conductive semiconductor layer having a light extraction surface; and a recombination suppression structure provided in vicinity of an end surface of the active layer, the recombination suppression structure having a bandgap larger than a bandgap of the active layer.