Deep-UV Light-Emitting Element With Transparent Tunnel Junction Layers
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Solution Overview
Problem
GaN or InGaN materials strongly absorb light in the deep ultraviolet region, reducing light extraction efficiency in light-emitting elements with tunnel junction configurations.
Innovation Solution
A light-emitting element design featuring a p-type layer with a high acceptor concentration layer and a low acceptor concentration layer, and an n-type contact layer with a high donor concentration layer and a low donor concentration layer, all formed using AlxGayIn1-x-yN, where the band gaps of these layers are larger than the light-emitting layer, to minimize absorption and enhance light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a tunnel junction configuration is used with p-type GaN layer and n-type InGaN layer, then the light-emitting element can achieve efficient electron-hole recombination and light emission, but the p-type GaN layer or n-type InGaN layer strongly absorbs light in the deep ultraviolet region, reducing light extraction efficiency
Solution Approach 1:
The patent changes the material composition parameters of the contact layers by introducing AlxGayIn1-x-yN with specific aluminum content ratios. By adjusting the band gap parameters through compositional changes, the contact layers become transparent to deep ultraviolet light while maintaining their electrical functions, thus resolving the contradiction between light emission efficiency and light extraction efficiency
Solution Approach 2:
The patent uses composite AlxGayIn1-x-yN material that combines the advantages of different III-V semiconductor materials. This composite material achieves both the required electrical properties for tunnel junction formation and optical transparency in the deep ultraviolet region, simultaneously satisfying both light emission and light extraction requirements
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 design effectively suppresses light absorption by the n-type and p-type layers, enabling efficient deep ultraviolet light emission with improved light extraction efficiency.
Implementation Method 1
a second n-type contact layer that comprises AlxGayIn1-x-yN (0≤x+y≤1, 0≤x, y≤1), is located on the p-type layer and forms a tunnel junction with the p-type layer
Implementation Method 2
a light-emitting layer that is located on the first n-type contact layer and emits light at a wavelength of not less than 210 nm and not more than 365 nm
Data Source
AI summary
A light-emitting element includes a first n-type contact layer, a light-emitting layer that is located on the first n-type contact layer and emits light at a wavelength of not less than 210 nm and not more than 365 nm, a p-type layer that includes AlxGayIn1-x-yN (0≤x+y≤1, 0≤x, y≤1) and is located above the light-emitting layer, a second n-type contact layer that includes AlxGayIn1-x-yN (0≤x+y≤1, 0≤x, y≤1), is located on the p-type layer and forms a tunnel junction with the p-type layer, an n-electrode connected to the first n-type contact layer, and a p-electrode connected to the second n-type contact layer. Band gaps of the p-type layer and the second n-type contact layer are larger than a band gap of the light-emitting layer.