Nitride Semiconductor Stacked Body With N-Side Electron Barrier Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In nitride semiconductor light emitting devices, the uneven distribution of holes across the p-type and n-type cladding layers leads to reduced luminous efficiency due to insufficient carrier injection into the active layer, causing a deficiency of holes on the n-type cladding layer side and increased carrier loss through the Auger effect.
Innovation Solution
The introduction of an n-side electron barrier layer with a higher band gap energy, such as an AIGaN layer, is positioned near the n-type cladding layer to prevent low-energy electrons from entering the active layer, ensuring uniform carrier injection by accumulating electrons on the n-type cladding layer side and drawing corresponding holes into the active layer, thereby enhancing luminous efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional nitride semiconductor structure without an n-side electron barrier layer is used, then the device structure is simpler, but the carrier injection into the active layer is uneven and luminous efficiency is reduced
Solution Approach 1:
An n-side electron barrier layer with higher band gap energy than the active layer is introduced as an intermediary between the n-type cladding layer and the active layer. This barrier layer mediates electron transport by preventing low-energy electrons from directly entering the active layer, thereby improving carrier injection uniformity and luminous efficiency while maintaining reasonable structural complexity
2Device complexity
If electrons are allowed to freely enter the active layer from the n-type cladding layer, then the device structure is simpler, but carrier loss through the Auger effect increases and luminous efficiency decreases
Solution Approach 1:
The patent converts the potentially harmful effect of high electron concentration (which causes Auger effect and carrier loss) into a beneficial effect by using the n-side electron barrier layer to accumulate electrons on the n-type cladding layer side. This accumulation creates a reservoir that supplies electrons uniformly to the active layer, reducing carrier loss and improving luminous efficiency
3Productivity
If an n-side electron barrier layer is introduced to improve carrier injection uniformity, then luminous efficiency increases, but the device structure becomes more complex
Solution Approach 1:
The n-side electron barrier layer is introduced locally at the n-type cladding layer interface with the active layer, rather than modifying the entire device structure. This localized approach improves carrier injection uniformity and luminous efficiency while minimizing the increase in overall 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 improves luminous efficiency by ensuring uniform carrier injection into the active layer, reduces the Auger effect, and maintains charge neutrality, resulting in increased light emission and reduced carrier loss.
Implementation Method 1
insufficient carrier injection into the active layer, causing a deficiency of holes on the n-type cladding layer side and increased carrier loss through the Auger effect
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
According to one embodiment, the n-side electron barrier layer is provided at a region close to an end of the active layer on the n-type cladding layer side. The region is located within a range of an electron diffusion length from the active layer. The n-side electron barrier layer prevents electrons having energy which is not more than predetermined energy from being injected into the active layer.