Tunnel Junction Layer for Multi-Color LED Light Extraction
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Solution Overview
Problem
The existing configuration of light-emitting diodes with plural light-emitting parts laminated one above another across a tunnel junction layer often results in reduced light emission output due to incomplete extraction of emitted light.
Innovation Solution
A light-emitting diode structure featuring a tunnel junction part with a highly n-type impurities-doped layer between the third p-type and n-type layers, where the n-type impurities are concentrated at a higher level than in the n-type layer facing the second n-type layer, and the p-type impurities are concentrated at a higher level than in the first p-type layer, enhancing light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If plural light-emitting parts are laminated one above another across a tunnel junction layer, then the light-emitting diode can emit light at multiple wavelengths, but the light emission output is reduced because some light cannot be extracted to the outside
Solution Approach 1:
The patent divides the light-emitting diode into multiple independent light-emitting parts (first light-emitting part and second light-emitting part) separated by a tunnel junction layer. Each light-emitting part has its own p-type layer, n-type layer, and active layer, allowing them to emit light independently at different wavelengths while reducing mutual interference and improving light extraction efficiency.
Solution Approach 2:
The tunnel junction layer acts as an intermediary between the first and second light-emitting parts. It enables electrical connection for series operation while being transparent to light, allowing light from both parts to be extracted effectively without significant absorption or interference.
2Ease of operation
If a tunnel junction layer is introduced to connect multiple light-emitting parts in series, then forward current can be supplied to all parts, but the structural complexity increases
Solution Approach 1:
The tunnel junction layer serves multiple functions simultaneously: it provides electrical connection between light-emitting parts in series, maintains structural integrity of the multi-layer device, and remains transparent to light to minimize optical interference. This multi-functionality reduces the need for additional separate components.
Solution Approach 2:
The patent embeds the tunnel junction layer within the overall layer structure, nesting it between the first and second light-emitting parts. This integration allows the tunnel junction to be part of the monolithic structure grown by molecular beam epitaxy, reducing manufacturing steps compared to separate assembly approaches.
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 proposed structure improves light emission output by up to 10% compared to conventional designs, while maintaining lower forward voltage and reducing electrical resistance.
Implementation Method 1
the third p-type layer and the third n-type layer forming a tunnel junction
Data Source
AI summary
A method for manufacturing a tunnel junction layer using organic vapor phase deposition, the method including: a first process that supplies a first material gas containing a group III element, a second material gas containing a group V element, and a third material gas containing a dopant of a first conductivity type, onto a compound semiconductor layer on which the tunnel junction layer is to be laminated; a second process that stops supplying the first material gas, the second material gas and the third material gas, and supplies a fourth material gas containing a dopant of a second conductivity type opposite to the first conductivity type; and a third process that continues to supply the fourth material gas, and further supplies a fifth material gas containing a group III element and a sixth material gas containing a group V element.