UV Nitride LED Structure for Dislocation-Stable Light Output
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Solution Overview
Problem
Conventional nitride semiconductor light-emitting elements experience a decrease in light output over time due to dislocations from the active layer reaching the p-type contact layer, causing current concentration and metal element intrusion, which reduces their efficiency.
Innovation Solution
Incorporating a dislocation suppression structure-containing layer between the active layer and the p-type contact layer, with a p-type contact layer thickness of 10 nm to 30 nm, to prevent dislocations from reaching the p-type contact layer and enhance light output stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the p-type contact layer thickness is reduced to improve light output, then light output is improved, but dislocations reach the p-type contact layer causing current concentration and metal intrusion
Solution Approach 1:
An electron blocking layer is introduced as an intermediary between the active layer and the p-type contact layer. This layer serves as a mediator that simultaneously blocks dislocations from reaching the contact layer and prevents current concentration, while allowing the p-type contact layer to maintain its thin configuration for high light output.
Solution Approach 2:
The semiconductor layer structure is segmented into multiple functional layers: the active layer, the electron blocking layer, and the p-type contact layer. This segmentation allows each layer to perform its specific function independently, with the electron blocking layer specifically tasked with preventing dislocation propagation while maintaining overall device performance.
2Reliability
If the p-type contact layer thickness is increased to prevent dislocation reach, then dislocation-induced current concentration is suppressed, but light output decreases
Solution Approach 1:
The electron blocking layer acts as a protective intermediary that assumes the dislocation-blocking function, thereby allowing the p-type contact layer to remain thin and maintain high light output while still preventing dislocation-induced current concentration through the mediator layer.
Solution Approach 2:
The dislocation-blocking function is extracted from the p-type contact layer and assigned to a dedicated electron blocking layer. This separation of functions allows the contact layer to optimize for electrical contact and light output while the blocking layer optimizes for dislocation prevention.
3Reliability
If metal elements enter through dislocation sites, then current concentration occurs, but light output decreases over time with energization
Solution Approach 1:
The electron blocking layer, positioned to intercept dislocations, converts the potentially harmful dislocation paths into a controlled barrier. By blocking dislocations before they reach the contact layer, the structure prevents metal element intrusion and current concentration, thereby converting a defect pathway into a protective feature.
Solution Approach 2:
The electron blocking layer provides beforehand protection by being positioned upstream of the p-type contact layer in the dislocation propagation path. This prior cushioning prevents dislocations and associated metal elements from reaching the contact layer before they can cause harm, ensuring long-term stability.
Data Source
AI summary
A nitride semiconductor light-emitting element outputs ultraviolet light. The nitride semiconductor light-emitting element includes an active layer including a quantum well structure that generates the ultraviolet light, a dislocation suppression structure-containing layer being formed on the active layer and including a dislocation suppression structure that stops or bends a dislocation from the active layer; and a p-type contact layer being formed on the dislocation suppression structure-containing layer and having a thickness of not less than 10 nm and not more than 30 nm.