Lateral Inhomogeneous Superlattice for LED Conductivity and Transparency
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Solution Overview
Problem
Semiconductor emitting devices, such as LEDs and laser diodes, face inefficiencies due to compositional and doping inhomogeneities in semiconductor layers, leading to variations in refractive index and band gap energy, which affect light absorption and conductivity.
Innovation Solution
A short period superlattice semiconductor layer is designed with alternating barriers and wells, featuring transparent regions with high transmission coefficients and higher conductive regions to optimize light transmission and current flow, thereby balancing conduction and absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If semiconductor layers are made highly conductive to improve current flow, then electrical conductivity is improved, but light absorption increases reducing transmission efficiency
Solution Approach 1:
The patent implements lateral inhomogeneities within semiconductor layers, creating distinct transparent regions and conductive regions in different spatial locations. This allows different parts of the same layer to have different optical and electrical properties, enabling simultaneous light transmission and current conduction without requiring the entire layer to compromise either property.
Solution Approach 2:
The patent creates composite semiconductor structures by combining regions with different compositions and doping levels within a single layer. These composite layers integrate transparent portions (with lower doping and higher bandgap) and conductive portions (with higher doping and lower bandgap), achieving a material system that exhibits both high transparency and high conductivity when viewed as a whole structure.
2Ease of manufacture
If uniform composition is maintained throughout semiconductor layers, then manufacturing simplicity is preserved, but light transmission and conductivity cannot be simultaneously optimized
Solution Approach 1:
The patent introduces controlled local variations in composition and doping within semiconductor layers, creating spatially distinct regions with optimized properties for specific functions. This approach moves away from uniform composition to achieve superior device performance through localized property optimization.
Solution Approach 2:
The patent creates dynamic functional regions within the semiconductor structure where properties such as transparency and conductivity vary laterally. This allows the device to handle multiple functions (light transmission and current conduction) simultaneously through different spatial zones rather than requiring separate layers for each function.
3Loss of energy
If transparent regions are increased to improve light transmission, then optical transmission is improved, but conductivity decreases increasing voltage drop
Solution Approach 1:
The patent divides the semiconductor layer into segmented transparent regions and conductive regions that coexist laterally. This segmentation allows the light transmission function to be performed by transparent regions while the conductivity function is performed by conductive regions, eliminating the need to sacrifice one property for the other.
Solution Approach 2:
The patent resolves the trade-off by transitioning from a vertical stacking approach (where different layers perform different functions) to a lateral spatial distribution approach within the same layer plane. This dimensional shift allows multiple functions to coexist in the same vertical position but different lateral positions, achieving both transparency and conductivity simultaneously.
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 solution enhances the efficiency of light emitting devices by reducing light absorption and maintaining a desired voltage drop, improving conductivity and light transmission through the creation of conduction channels and transparent regions within the semiconductor layer.
Implementation Method 1
transparent regions, which are configured to reduce an amount of radiation that is absorbed in the layer
Implementation Method 2
higher conductive regions, which are configured to keep the voltage drop across the layer within a desired range
Data Source
AI summary
A device including one or more layers with lateral regions configured to facilitate the transmission of radiation through the layer and lateral regions configured to facilitate current flow through the layer is provided. The layer can comprise a short period superlattice, which includes barriers alternating with wells. In this case, the barriers can include both transparent regions, which are configured to reduce an amount of radiation that is absorbed in the layer, and higher conductive regions, which are configured to keep the voltage drop across the layer within a desired range.