Quartz Glass Outcoupling Layer for UV LED Light Extraction
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Solution Overview
Problem
Existing radiation-emitting devices, such as light-emitting diodes (LEDs) and laser diodes, face inefficiencies in radiation outcoupling due to the use of organic adhesives and materials that degrade under UV radiation, leading to reduced service life and performance.
Innovation Solution
The development of a radiation-emitting device that utilizes a carrier formed from sapphire and/or AlN, with a semiconductor layer sequence epitaxially deposited on it, and incorporates a radiation outcoupling layer based on quartz glass. This configuration reduces refraction and back-reflection of electromagnetic radiation, enhancing outcoupling efficiency and eliminating the need for organic adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If organic adhesives are used to bond the radiation outcoupling layer to the carrier, then the device can be manufactured with simpler processes, but the service life is reduced and performance degrades under UV radiation
Solution Approach 1:
The patent removes organic adhesives from the device structure entirely, replacing them with a direct bonding interface between the radiation outcoupling layer and the carrier. This extraction eliminates the degradation pathway that organic materials experience under UV radiation, thereby resolving the contradiction between ease of manufacture and long-term reliability.
Solution Approach 2:
The patent replaces durable inorganic materials (carrier and outcoupling layer) that would last indefinitely with organic adhesives that are cheap and easy to apply but have limited service life under UV radiation. This creates the contradiction that the invention then resolves by removing the adhesives entirely.
2Device complexity
If conventional materials are used for the carrier and radiation outcoupling layer, then the device structure is simpler, but refraction and back-reflection reduce outcoupling efficiency
Solution Approach 1:
The patent changes the refractive index parameter of the radiation outcoupling layer by selecting materials (sapphire, AlN, or AlGaN) with specific refractive indices that match or closely approximate the carrier material. This parameter matching minimizes refraction and back-reflection at the interface, thereby maximizing radiation outcoupling efficiency without significantly increasing device complexity.
Solution Approach 2:
The patent employs composite material structures where the carrier and radiation outcoupling layer are both selected from the same material family (sapphire, AlN, or AlGaN), creating a homogenous optical interface that reduces reflection losses while maintaining structural integrity and enabling efficient radiation outcoupling.
3Stability of the object's composition
If the radiation outcoupling layer is bonded to the carrier, then structural stability is improved, but material degradation under radiation reduces service life
Solution Approach 1:
The patent eliminates the use of organic adhesives that are susceptible to UV radiation degradation, replacing them with a direct inorganic-to-inorganic bonding interface. This removal of the weak link (organic adhesive) preserves structural stability while eliminating the degradation mechanism, thereby extending service life indefinitely under UV radiation exposure.
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 proposed solution achieves higher light yield and extended service life by minimizing radiation reflection and degradation, allowing for efficient operation of the radiation-emitting device, particularly in UV applications.
Implementation Method 1
The radiation outcoupling layer has a refractive index for the electromagnetic radiation generated by the active region, the refractive index being between a refractive index of the carrier and a refractive index of a medium surrounding the device
Implementation Method 2
The semiconductor layer sequence comprises an active region for generating electromagnetic radiation
Implementation Method 3
The semiconductor layer sequence is applied onto the carrier, in particular is epitaxially deposited on the carrier
Data Source
AI summary
A radiation-emitting device includes a carrier formed to include sapphire and/or AlN. A semiconductor layer sequence is applied onto the carrier. A radiation outcoupling layer is arranged on the side of the carrier facing away from the semiconductor layer sequence, wherein the semiconductor layer sequence includes an active region for generating electromagnetic radiation, and wherein the radiation outcoupling layer has a refractive index for the electromagnetic radiation generated by the active region which is between the refractive index of the carrier and the refractive index of the medium surrounding the component. The radiation outcoupling layer is based on quartz glass. Furthermore, a method for manufacturing an optoelectronic device is disclosed.