Nitride Semiconductor LED Ohmic Contact Segmentation
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Solution Overview
Problem
Nitride-based semiconductor light-emitting devices, particularly deep ultraviolet (DUV) LEDs, face challenges in achieving high light extraction efficiency (LEE), which is crucial for various applications including sterilization, medical fields, and pollutant decomposition.
Innovation Solution
The design incorporates a nitride-based semiconductor light-emitting device structure with an n-type and p-type nitride-based semiconductor layer, an active layer, and an ohmic contact layer that discontinuously covers the p-type nitride-based semiconductor layer, allowing for improved light reflection and extraction by forming a concavo-convex structure on the p electrode, reducing optical loss, and optimizing the area coverage of the ohmic contact layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an ohmic contact layer continuously covers the p-type nitride-based semiconductor layer, then electrical contact is improved, but light extraction efficiency deteriorates due to increased absorption losses
Solution Approach 1:
The ohmic contact layer is divided into multiple separate regions rather than forming a continuous layer. This segmentation allows light to pass through the gaps between contact regions, reducing absorption losses while maintaining sufficient electrical contact areas for reliable device operation
Solution Approach 2:
Different regions of the device are given different properties: regions with ohmic contact layers are optimized for electrical conduction, while regions without contact layers are optimized for light extraction. This local differentiation allows each region to perform its primary function efficiently
2Reliability
If the p electrode area is increased to improve electrical contact, then electrical performance is improved, but light absorption by the electrode increases, reducing light extraction efficiency
Solution Approach 1:
The p electrode is segmented into multiple separate contact regions that correspond to the discontinuous ohmic contact layer regions. This segmentation ensures electrical contact is made only where necessary, minimizing the total electrode area that would otherwise absorb light
Solution Approach 2:
The discontinuous ohmic contact layer serves as an intermediary between the p-type semiconductor layer and the p electrode. It provides the necessary electrical contact interface while its discontinuous structure prevents direct large-area contact between the electrode and semiconductor, reducing light absorption
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
This configuration enhances light extraction efficiency, increasing the device's luminance and reducing absorption losses, thereby improving the overall performance of the nitride-based semiconductor light-emitting devices.
Implementation Method 1
An ohmic contact layer discontinuously covers an upper surface of the p-type nitride-based semiconductor layer
Implementation Method 2
An active layer is formed on the n-type nitride-based semiconductor layer and a p-type nitride-based semiconductor layer formed on the active layer
Data Source
AI summary
A nitride-based semiconductor light-emitting device includes an n-type nitride-based semiconductor layer, an active layer, a p-type nitride-based semiconductor layer, an ohmic contact layer covering a portion of the p-type nitride-based semiconductor layer upper surface, and a p electrode including a first portion contacting the p-type nitride-based semiconductor layer and a second portion contacting the ohmic contact layer.