GaN LED with AlGaN Electron Blocking Layer
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Solution Overview
Problem
Semiconductor light-emitting elements, such as LEDs, face efficiency drops (droop phenomenon) at high electric current densities due to poor carrier infusion efficiency and dopant interdiffusion, leading to reduced light-emitting intensity.
Innovation Solution
A GaN-based semiconductor light-emitting element with a concave/convex structured diffusion prevention layer between p-type semiconductor layers, specifically an AlGaN electron blocking layer, is used to suppress dopant interdiffusion and enhance carrier injection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a p-type semiconductor layer is formed on an active layer to improve carrier injection efficiency, then light-emitting efficiency is improved, but dopant interdiffusion occurs leading to reduced performance
Solution Approach 1:
An electron blocking layer is introduced as an intermediary between the active layer and the p-type semiconductor layer. This layer prevents direct contact between the active layer and p-type dopants, thereby blocking dopant diffusion while still allowing effective carrier injection. The electron blocking layer acts as a mediator that resolves the conflict between improving light-emitting efficiency and maintaining dopant distribution stability.
Solution Approach 2:
The p-type semiconductor layer is divided into multiple sub-layers with different doping concentrations and compositions. By segmenting the layer structure, the patent creates a gradient that reduces dopant diffusion while maintaining effective hole injection. The segmented structure allows different regions to perform specialized functions, preventing uniform dopant spread.
2Illumination intensity
If high electric current density is applied to increase light-emitting intensity, then brightness is improved, but droop phenomenon occurs reducing efficiency
Solution Approach 1:
The electron blocking layer is strategically positioned at the critical interface between the active layer and p-type layer, where carrier injection occurs. By concentrating the dopant-blocking function at this specific location rather than throughout the entire structure, the patent achieves effective droop suppression without compromising overall carrier injection efficiency. The local quality modification at the interface resolves the droop phenomenon while maintaining high light-emitting efficiency.
3Reliability
If dopant concentration is increased to improve carrier injection, then carrier injection efficiency is improved, but dopant diffusion into active layer increases
Solution Approach 1:
The electron blocking layer serves as a protective intermediary that allows high dopant concentrations in the p-type layer without causing harmful diffusion into the active layer. This mediator layer accepts the high dopant concentration needed for reliable carrier injection while preventing the harmful side effect of dopant migration into the active region.
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 effectively maintains high light-emitting intensity even at high electric current densities by preventing Mg dopant diffusion, thereby reducing the droop phenomenon and improving overall light-emitting efficiency.
Implementation Method 1
decreasing crystal defects and suppressing diffusion of impurities into active layers
Implementation Method 2
a study of forming an area where positive holes collect in the interface between the EBL layer and the p-GaN layer (two-dimensional hole gas-like layer), and suppressing the injection of holes into the active layer
Implementation Method 3
the light-emitting intensity of an LED is proportional to the electric current
Data Source
AI summary
Provided is a semiconductor light-emitting element in which dopant interdiffusion is suppressed, the efficiency at which a carrier is infused into an active layer is improved, and there is less of a decrease in light-emitting intensity (droop) during high-current driving at a high light-emitting efficiency. The semiconductor light-emitting element composed of a GaN-based semiconductor includes an n-type semiconductor layer, an active layer formed on the n-type semiconductor layer, a first semiconductor layer formed on the active layer and having a concave/convex structure layer in the surface, and a second semiconductor structure layer doped with Mg and formed on the first semiconductor layer.