Stepped Light Extracting Structure for III-V Nitride Semiconductor Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional light emitting devices using III-V nitride semiconductors face inefficiencies in light extraction due to the refractive index mismatch between semiconductor layers, leading to reduced external quantum efficiency.
Innovation Solution
A light emitting device with a novel light extracting structure formed on the side surface of a semiconductor layer closer to the substrate, incorporating a transmissive layer with a refractive index lower than the semiconductor layer, which enhances light extraction efficiency by altering the critical angle of incident light and facilitating its transmission rather than reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional light emitting device structure is used, then the device structure is simple, but the light extraction efficiency is low due to refractive index mismatch
Solution Approach 1:
A transmissive layer with refractive index intermediate between the semiconductor layer and air is introduced as a mediator. This layer reduces the refractive index mismatch at the interface, thereby decreasing reflection loss and improving light extraction efficiency without significantly complicating the device structure
Solution Approach 2:
The refractive index parameter of the interface is modified by introducing the transmissive layer. By changing the optical parameter (refractive index) at the semiconductor-air interface, the light extraction efficiency is improved while maintaining structural simplicity
2Loss of energy
If a light extracting structure is formed on the side surface, then the light extraction efficiency is improved, but the device structure becomes more complex
Solution Approach 1:
The light extracting structure is formed locally on the side surface of the semiconductor layer rather than throughout the entire device. This localized approach improves light extraction at critical interfaces while minimizing the overall structural complexity and maintaining ease of manufacture
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 light extraction efficiency by maximizing the transmission of emitted light through the transmissive layer, thereby enhancing the overall performance of the light emitting device.
Implementation Method 1
a transmissive layer having a refractive index lower than that of a semiconductor layer on a side surface of the semiconductor layer between a substrate and an active layer
Implementation Method 2
enhances light extraction efficiency by altering the critical angle of incident light and facilitating its transmission rather than reflection
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Disclosed is a light emitting device. The light emitting device includes a light emitting structure layer including a first conductive type semiconductor layer (121), an active layer (123) on the first conductive type semiconductor layer, and a second conductive type semiconductor layer (125) on the active layer, a first light extracting structure (S1) formed on an outer portion of the first conductive type semiconductor layer and having a plurality of side surfaces and a plurality of upper surfaces formed in a step structure, and a transmissive layer (140) on the first light extracting structure of the first conductive type semiconductor layer.