Infrared LED Al Composition Optimization for Defect Reduction
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Solution Overview
Problem
Infrared LEDs used in gas sensors struggle to achieve sufficient emission intensity, leading to low signal intensity and limited application due to high defect density in the vicinity of the second compound semiconductor layer, which deactivates carriers and reduces quantum emission efficiency.
Innovation Solution
The infrared light emitting device incorporates a semiconductor substrate with specific compound semiconductor layers, including a light emitting layer with In and Sb, and a second compound semiconductor layer with Al and Sb, where the Al composition and film thickness are optimized to reduce line defect density by applying a line defect filter layer, ensuring the product of the difference in Al composition and film thickness between the second compound semiconductor layer and the light emitting layer is less than or equal to the product of the differences in the first B and A layers, thereby bending line defects and enhancing carrier confinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the emission intensity of infrared LEDs is increased, then the S/N ratio increases, but the device complexity increases due to the need for precise control of Al composition and film thickness parameters
Solution Approach 1:
The patent applies parameter changes by precisely controlling the Al composition ratio (nAl) and film thickness (m) parameters of the compound semiconductor layer to optimize emission intensity. By establishing specific parameter ranges and relationships between multiple parameters, the invention achieves high emission intensity while managing device complexity through systematic parameter optimization rather than structural complexity
Solution Approach 2:
The invention introduces dynamic control mechanisms by allowing flexible adjustment of Al composition and film thickness within optimized ranges. The patent enables dynamic optimization of emission characteristics through controllable parameter variations during manufacturing, allowing the device to achieve desired emission intensity while adapting to different application requirements
2Measurement precision
If a filter is provided on the light emitting device side to perform spectral analysis, then the wavelength spectrum can be analyzed, but the cost increases and the sensitivity decreases due to weakened infrared ray intensity
Solution Approach 1:
The patent extracts the spectral filtering function from a separate external filter component and integrates it directly into the light emitting device structure through the compound semiconductor layer. By incorporating the filtering capability within the LED itself, the invention eliminates the need for separate filters, thereby maintaining infrared ray intensity and sensitivity while achieving spectral analysis capability
Solution Approach 2:
The invention merges multiple functions into a single integrated structure: the compound semiconductor layer simultaneously serves as the light emitting layer and the spectral filtering layer. This consolidation of emission and filtering functions in one component reduces system complexity, maintains optical intensity, and improves overall device reliability
3Illumination intensity
If an incandescent bulb is used as the infrared light source, then the infrared rays can be emitted, but the life is short requiring frequent replacement
Solution Approach 1:
The patent replaces the thermal radiation mechanism of incandescent bulbs with the electroluminescence mechanism of semiconductor LEDs. By substituting the mechanical/thermal light generation system with a solid-state semiconductor system, the invention achieves the same infrared emission function with significantly extended operational life and improved reliability
Solution Approach 2:
The invention changes the fundamental operating parameters from thermal radiation at high temperatures to electroluminescence at lower temperatures. This parameter change from thermal to electrical excitation mechanism enables the light source to operate with much lower power consumption and significantly longer lifespan while maintaining infrared emission capability
4Reliability
If the line defect density is reduced by optimizing Al composition and film thickness, then the quantum emission efficiency increases, but the manufacturing precision requirements increase
Solution Approach 1:
The patent establishes specific parameter ranges and relationships for Al composition (nAl) and film thickness (m) that optimize quantum emission efficiency while reducing line defect density. By defining concrete parameter boundaries and interrelationships, the invention transforms complex manufacturing precision requirements into manageable parameter control specifications
Solution Approach 2:
The compound semiconductor layer acts as an intermediary structure that mediates between the substrate and the light emitting layer. By optimizing this intermediate layer's parameters, the invention reduces the propagation of line defects from the substrate while maintaining high quantum emission efficiency, effectively decoupling the manufacturing precision requirements
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 maximizes quantum emission efficiency and emission intensity by reducing line defect density and carrier deactivation, enabling higher sensitivity and wider application of infrared LEDs in gas sensing and other analytical instruments.
Implementation Method 1
a forward current is passed through the pn junction diode, and electrons and holes are recombined in the light emitting layer to emit infrared rays
Implementation Method 2
the product of the difference in Al composition and film thickness between the second compound semiconductor layer and the light emitting layer is less than or equal to the product of the differences in the first B and A layers, thereby bending line defects
Implementation Method 3
applying a line defect filter layer, ensuring the product of the difference in Al composition and film thickness between the second compound semiconductor layer and the light emitting layer is less than or equal to the product of the differences in the first B and A layers, thereby bending line defects and enhancing carrier confinement
Data Source
AI summary
Provided is an infrared light emitting device with high emission intensity. The infrared light emitting device includes: a semiconductor substrate; a first compound semiconductor layer; a light emitting layer containing at least In and Sb and having a predetermined range(s) of Al or Al and Ga proportion(s); a third compound semiconductor layer; and a second compound semiconductor layer containing at least In, Al, and Sb and having a predetermined range(s) of Al or Al and Ga proportion(s), in which the first compound semiconductor layer includes, in the stated order, a first A layer, a first B layer, and a first C layer, each containing at least In and Sb and having a predetermined range(s) of Al or Al and Ga proportion(s), and the proportion(s) of the Al composition or the Al composition and the Ga composition of each layer satisfy a predetermined relation(s).