Light Emitting Device Electron Blocking Layer Al Memory-Effect
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Solution Overview
Problem
Nitride semiconductor light emitting devices face efficiency degradation due to the Al memory-effect, which reduces hole injection into the electron blocking layer, leading to lower light efficiency.
Innovation Solution
Incorporating an interrupted diffusion layer in the electron blocking layer to enhance Mg ion concentration and improve the uniformity of Al and Mg ion concentrations, thereby increasing hole injection efficiency and light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Mg incorporation is performed in an electron blocking layer with high Al content, then electron blocking function is improved, but hole injection efficiency deteriorates due to Al memory-effect
Solution Approach 1:
The electron blocking layer is divided into multiple regions with different Al compositions: a first electron blocking layer with higher Al content for electron blocking, and a second electron blocking layer with lower Al content for improved hole injection. This segmentation allows each region to optimize its function without the Al memory-effect limiting overall performance.
Solution Approach 2:
Different regions of the electron blocking layer are assigned different material compositions tailored to their specific functions. The first electron blocking layer uses high Al content material for electron blocking, while the second electron blocking layer uses lower Al content material to facilitate hole injection, allowing each local region to have optimal properties for its intended purpose.
2Reliability
If Al content in electron blocking layer is increased, then electron blocking capability is enhanced, but Mg incorporation efficiency decreases
Solution Approach 1:
The electron blocking layer is segmented into regions with different Al contents. The first electron blocking layer has higher Al content for electron blocking capability, while the second electron blocking layer has lower Al content that allows effective Mg incorporation, thus resolving the conflict between Al content and Mg incorporation efficiency.
Solution Approach 2:
The Al composition parameter is varied across different regions of the electron blocking layer. By changing the Al content parameter from high in the first electron blocking layer to lower in the second electron blocking layer, the patent enables both electron blocking capability and Mg incorporation efficiency to be optimized in their respective regions.
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 improves electron blocking function and hole injection efficiency, resulting in enhanced light efficiency by increasing Mg ion concentration and maintaining higher Al ion concentration without additional Al supply, thus overcoming the Al memory-effect.
Implementation Method 1
the incorporation of magnesium (Mg) is competitively performed under the environment having a higher Al content of an electron blocking region, so that the level of Mg becomes lowered in the initial stage of growing a p type electron blocking layer
Data Source
AI summary
Disclosed are a light emitting device, a method of fabricating the light emitting device, a light emitting device package, and a lighting system. The light emitting device includes a first conductive semiconductor layer, an active layer on the first conductive semiconductor layer, an electron blocking layer on the active layer, and a second conductive semiconductor layer on the electron blocking layer. The electron blocking layer includes a first electron blocking layer and an interrupted diffusion layer on the first electron blocking layer.