Light Emitter with PN Junction for Leakage Current Suppression
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Solution Overview
Problem
Semiconductor light emitters face leakage current issues due to shared conductivity type between n-type posts and semiconductor layers, affecting the efficiency and stability of light emission.
Innovation Solution
A light emitter design with a substrate, first and second semiconductor layers of different conductivity types, a light emitting layer, and a third semiconductor layer with a protruding/recessed structure, forming a PN junction to suppress leakage current, and a potential applicator to apply reverse bias and control potentials across the layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If n-type posts and n-type semiconductor layer have the same conductivity type to simplify structure, then manufacturing is easier, but leakage current flows through the n-type posts
Solution Approach 1:
The patent applies local quality by creating a PN junction specifically at the interface between the first semiconductor layer and third semiconductor layer, where conductivity type changes from n-type to p-type locally. This localized conductivity change suppresses leakage current through the posts while maintaining overall structural simplicity, resolving the contradiction between ease of manufacture and reliability.
2Productivity
If current is injected into the light emitting layer via electrodes coupled to n-type and p-type layers, then light emission function is achieved, but leakage current flows through n-type posts
Solution Approach 1:
The patent introduces a first semiconductor layer with p-type conductivity as an intermediary between the n-type third semiconductor layer and the light emitting layer. This intermediary layer forms a PN junction that acts as a barrier to leakage current while allowing the current injection function to proceed, thus maintaining light emission efficiency while suppressing leakage.
3Ease of manufacture
If semiconductor layers are grown on substrate with different lattice constants, then device fabrication is enabled, but dislocation occurs in the layers
Solution Approach 1:
The patent segments the semiconductor structure into multiple layers (third semiconductor layer, first semiconductor layer, light emitting layer, second semiconductor layer) with different conductivity types and lattice characteristics. This segmentation allows each layer to be optimized for its specific function while managing dislocation propagation, enabling device fabrication on suitable substrates while controlling dislocation density in critical layers.
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 leakage current, stabilizes current injection into the light emitting layer, reduces dislocation, and enhances the quality and efficiency of light emission, leading to improved laser oscillation and reduced noise.
Implementation Method 1
a PN junction can be formed between the first semiconductor layer and the third semiconductor layer, allowing suppression of leakage of current into the third semiconductor layer
Implementation Method 2
a light emitting layer provided between the first semiconductor layer and the second semiconductor layer and capable of emitting light when current is injected into the light emitting layer
Data Source
AI summary
A light emitter includes a substrate, a first semiconductor layer having a first conductivity type, a second semiconductor layer having a second conductivity type different from the first conductivity type, a light emitting layer provided between the first semiconductor layer and the second semiconductor layer and capable of emitting light when current is injected into the light emitting layer, and a third semiconductor layer provided between the substrate and the first semiconductor layer and having the second conductivity type, in which the first semiconductor layer is provided between the third semiconductor layer and the light emitting layer, and the third semiconductor layer has a protruding/recessed structure.