Light-Emitting Device With 3D Distributed Bragg Reflector
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Solution Overview
Problem
Conventional light-emitting devices have limited light extraction efficiency due to the design of their reflector layers and electrode configurations, which hinder the effective reflection and emission of light from the active layer.
Innovation Solution
The implementation of a three-dimensional distributed Bragg reflector (DBR) layer between the transparent conductive layer and the P-type semiconductor layer, along with a P-side electrode pad and branch electrode configuration, enhances light extraction by uniformly reflecting light and preventing absorption by the electrode, while ensuring efficient current distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a mesh-type DBR with openings is used to reflect light, then light extraction efficiency is improved, but the electrode cannot make direct contact with the semiconductor layer
Solution Approach 1:
The device is divided into two functional regions: a mesh-type DBR region for light extraction and an opening region for electrode contact. The mesh-type DBR includes multiple openings that segment the structure, allowing different areas to perform different functions - light reflection in covered areas and electrode contact in opening areas.
Solution Approach 2:
Different regions of the device are given different properties: the mesh-type DBR regions provide high reflectivity for light extraction, while the opening regions provide direct electrical contact between the electrode and semiconductor layer. Each region is optimized for its specific function.
2Loss of energy
If a reflector layer is formed under the P-side electrode to reflect light, then light extraction efficiency is improved, but the reflector must be made of conductive materials which may absorb light
Solution Approach 1:
The light reflection function is extracted from the conductive electrode and assigned to a separate mesh-type DBR structure. The DBR is positioned between the electrode and semiconductor layer to reflect light away from the electrode, preventing absorption while maintaining electrical contact functionality.
Solution Approach 2:
The mesh-type DBR acts as an intermediary structure between the electrode and semiconductor layer. It provides the light reflection function that would otherwise require the conductive electrode to perform, thereby preventing the electrode from absorbing light while still allowing electrical contact through its openings.
3Device complexity
If the P-side electrode is disposed directly on the P-type semiconductor layer, then device structure is simplified, but light emitted toward the electrode is absorbed
Solution Approach 1:
The mesh-type DBR is introduced as an intermediary layer between the P-side electrode and the P-type semiconductor layer. This intermediary structure reflects light away from the electrode while allowing the electrode to maintain direct contact with the semiconductor layer through its openings, thus preventing light absorption without adding significant structural complexity.
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 significantly improves light extraction efficiency by reflecting light emitted from the active layer and distributing current uniformly, leading to enhanced performance in light-emitting devices.
Implementation Method 1
a three-dimensional distributed Bragg reflector (DBR) layer between the transparent conductive layer and the P-type semiconductor layer
Data Source
AI summary
A structure of a light-emitting device includes the following components: a substrate; an epitaxial structure on the substrate, the epitaxial structure including at least a first conductivity type semiconductor layer, a light-emitting active layer, and a second conductivity type semiconductor layer; a first electrode on the first conductivity type semiconductor layer; a transparent conductive layer between the first electrode and the first conductivity type semiconductor layer; and a three-dimensional distributed Bragg reflector (DBR) layer between the transparent conductive layer and the first conductivity type semiconductor layer.