Tunnel-Junction Light-Emitting Element for Independent Blue-Green Control
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Solution Overview
Problem
Current light-emitting elements with semiconductor stacked structures struggle to independently control the lighting of different light-emitting portions, particularly those with tunnel junction layers, which limits their ability to emit specific wavelengths efficiently.
Innovation Solution
A light-emitting element design featuring a first and second light-emitting portion, each with a nitride semiconductor stacked body, tunnel junction layers, and distinct electrode configurations, allowing for individual control of lighting by varying the potential applied to p-side and n-side electrodes, and utilizing a transmissive conductive film with lower resistivity to facilitate current diffusion and reduce forward voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a tunnel junction layer is inserted between multiple active layers with different emission wavelengths, then the semiconductor stacked structure can emit multiple wavelengths, but individual control of lighting for each light-emitting portion becomes difficult
Solution Approach 1:
The patent divides the semiconductor stacked structure into multiple independent light-emitting portions, each with its own p-side electrode and n-side electrode. The tunnel junction layer is segmented into multiple regions, with each region associated with a specific active layer and controllable through dedicated electrodes. This segmentation enables independent control of each light-emitting portion while maintaining multi-wavelength emission capability.
Solution Approach 2:
The patent introduces n-type cladding layers as intermediary structures between the tunnel junction layer and the active layers. These cladding layers serve as current distribution mediators that can be selectively activated through the n-side electrodes, enabling independent control of each light-emitting portion. The cladding layers act as intermediaries that decouple the control mechanisms while maintaining electrical connectivity.
2Adaptability or versatility
If multiple active layers with different emission wavelengths are stacked, then the device can emit mixed light with adjustable chromaticity, but light propagation between adjacent units increases
Solution Approach 1:
The patent applies local quality by creating distinct optical isolation regions between adjacent light-emitting portions. The n-type cladding layers and tunnel junction regions are locally optimized to prevent light propagation while maintaining electrical functionality. This local optimization allows each light-emitting portion to maintain its specific emission characteristics without interference from adjacent units.
3Ease of manufacture
If conventional electrode configurations are used in semiconductor stacked structures with tunnel junctions, then manufacturing is simplified, but forward voltage remains high and current diffusion is limited
Solution Approach 1:
The patent changes the electrical parameters of the electrode configuration by introducing n-type cladding layers with optimized doping concentrations and thicknesses. These parameter changes enable better current diffusion and reduced forward voltage while maintaining manufacturing feasibility. The tunnel junction layer parameters are also optimized to achieve lower forward voltage without complicating the manufacturing process.
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
Enables independent control of blue and green light emission, allowing for mixed light output with adjustable chromaticity, reducing forward voltage, and minimizing light propagation between adjacent units, thus enhancing wavelength extraction efficiency.
Implementation Method 1
forming a transmissive conductive film having a resistivity lower than a resistivity of the second n-type layer on the second p-type layer
Implementation Method 2
a first active layer disposed on the first n-type layer... a second active layer disposed on the fourth n-type layer
Data Source
AI summary
A light emitting element includes a first light emitting portion and a second light emitting portion. The first light emitting portion includes a first stacked body having a first n-type layer, a first active layer, a first p-type layer, a first tunnel junction layer, and a second n-type layer. The second light emitting portion includes a second stacked body having a third n-type layer, a second p-type layer, a second tunnel junction layer, a fourth n-type layer, a second active layer, a third p-type layer, and a transmissive conductive film. A resistivity of the second n-type layer is higher than a resistivity of the transmissive conductive film. A thickness of the second n-type layer is larger than a thickness of the transmissive conductive film.