LED Mesa Structure Suppressing Edge Recombination
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Solution Overview
Problem
The miniaturization of light emitting diodes (LEDs) leads to increased non-emission recombination at the edge portions of the light emitting layer, reducing light-emitting efficiency, and existing solutions require complex manufacturing steps to improve efficiency.
Innovation Solution
A light emitting diode with a columnar laminated structure featuring a mesa structure where the second compound semiconductor layer is formed apart from the edge portion, with a second electrode on the top surface, preventing current flow near the side walls and enhancing light output from both the top and side surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the light emitting diode is miniaturized, then the area is reduced for application to printer or display, but non-emission recombination at edge portions increases and light-emitting efficiency is reduced
Solution Approach 1:
The patent applies local quality by creating a mesa structure where the second compound semiconductor layer is selectively removed from edge portions, resulting in different structural characteristics at different locations. The central region maintains the full laminated structure while edge regions have the second layer removed, suppressing non-emission recombination at edges without affecting the overall miniaturization
Solution Approach 2:
The second compound semiconductor layer is segmented into a first portion (at edge portions) and a second portion (at central region), allowing differential treatment of edge and central regions to optimize both miniaturization and light-emitting efficiency
2Loss of energy
If a recombination suppressing structure is provided near end surface of light emitting layer, then light-emitting efficiency is improved, but manufacturing steps become complex requiring formation and oxidation of crystalized film through whole surface and patterning
Solution Approach 1:
The patent extracts the second compound semiconductor layer from edge portions to create the mesa structure, eliminating the need for separate recombination suppressing structures. This extraction approach achieves edge portion non-emission recombination suppression through a single growth process rather than multiple processing steps including oxidation and patterning
Solution Approach 2:
The mesa structure is formed during the initial growth process of the compound semiconductor layers, incorporating the edge portion treatment into the fundamental structure formation rather than adding subsequent processing steps. The selective removal of the second layer is performed as part of the layer formation sequence
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 simplifies the manufacturing process while significantly improving light-emitting efficiency and increasing the light output area by minimizing non-emission recombination and allowing light emission from both surfaces.
Implementation Method 1
a light emitting layer 23 formed of a compound semiconductor... light is outputted at least from the top surface and a side surface of the second portion of the second compound semiconductor layer
Data Source
AI summary
A light emitting diode including: a columnar laminated structure 20 in which a first compound semiconductor layer 21, a light emitting layer 23, and a first portion 22A of a second compound semiconductor layer are laminated; a first electrode 31 electrically connected to the first compound semiconductor layer 21; and a second electrode 32. A second portion 22B of the second compound semiconductor layer is formed on the first portion 22A of the second compound semiconductor layer, apart from an edge portion 22a3 of the first portion 22A of the second compound semiconductor layer, the second electrode 32 is formed at least on a top surface of the second portion 22B of the second compound semiconductor layer, and light is outputted at least from the top surface 22b1 and a side surface 22b2 of the second portion 22B of the second compound semiconductor layer.