Front-Side Emitting Mid-Infrared LED with GaSb Substrate
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Solution Overview
Problem
Conventional mid-infrared LEDs based on antimonide-arsenide heterostructures face challenges such as lower internal conversion efficiency due to Auger recombination and free-carrier absorption, requiring higher current densities and increased heat dissipation, along with difficulties in light extraction and compatibility with existing high-brightness LED technologies.
Innovation Solution
The development of mid-infrared high-brightness LEDs with front-side emission using gallium antimonide (GaSb) semiconductor substrates and epitaxial heterostructures of indium arsenide (InAs), gallium arsenide (GaAs), and Aluminium Antimonide (AlSb) alloys, featuring cascaded double heterostructure confinement light emission stages and optimized surface features for light extraction, enabling compatibility with existing packaging and drive technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional antimonide-arsenide heterostructures are used for mid-infrared LED emission, then light emission can be achieved across mid-infrared wavelengths, but internal conversion efficiency is reduced due to Auger recombination and free-carrier absorption
Solution Approach 1:
The active region is segmented into multiple quantum wells separated by barrier layers, allowing independent optimization of each well for reduced Auger recombination while maintaining overall emission efficiency across the mid-infrared spectrum
Solution Approach 2:
The patent employs composite heterostructure materials combining different semiconductor compounds with tailored band structures, creating a composite system that suppresses free-carrier absorption and Auger recombination while enabling broad mid-infrared emission
2Illumination intensity
If higher current densities are applied to overcome low internal conversion efficiency, then light emission intensity can be maintained, but heat dissipation requirements increase
Solution Approach 1:
The patent optimizes structural parameters including quantum well thickness, barrier layer composition, and doping profiles to achieve high emission intensity at reduced current densities, thereby lowering heat generation while maintaining required light output levels
3Ease of manufacture
If conventional LED die structures are used, then manufacturing can follow existing processes, but light extraction efficiency is limited due to total internal reflection
Solution Approach 1:
The patent incorporates curved or patterned surface structures on the LED die, using curvature to alter light propagation paths and enable extraction of light that would otherwise be trapped by total internal reflection, while remaining compatible with standard manufacturing processes
Solution Approach 2:
The patent employs wavelength-specific optical coatings and surface treatments tailored to mid-infrared emission wavelengths, optimizing light extraction efficiency for the specific emission spectrum while maintaining compatibility with existing fabrication workflows
4Quantity of substance
If mid-infrared LED structures are developed for specific wavelengths, then emission at those wavelengths can be achieved, but compatibility with existing high-brightness LED packaging and drive technologies is reduced
Solution Approach 1:
The patent designs the LED structure with universal features including standardized die dimensions, common electrical contact configurations, and broad-spectrum emission capability, enabling the device to interface with existing high-brightness LED packaging and drive circuits while maintaining mid-infrared emission performance
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 solution enables efficient light emission across a broad mid-infrared range (3 to 20 μm) with improved heat management and compatibility with existing high-brightness LED technologies, facilitating applications in image illumination, spectroscopy, and communication links.
Implementation Method 1
as electrical current is applied to the junctions, electrons and holes combine with each other and emit photons. The energy contained in the emitted photos corresponds to the energy difference between the respective holes and electrons.
Implementation Method 2
Several combinations of antimonide-arsenide layers can provide a double-heterostructure confinement configuration for confining charge carriers to the light emitting alloys, superlattices, or quantum wells.
Implementation Method 3
Light generated within the heterostructures can be extracted from a die with combinations of surface features and coatings, such that light can escape which would otherwise be mostly confined to the die because of total internal reflection.
Data Source
AI summary
A device emitting mid-infrared light that comprises a semiconductor substrate of GaSb or closely related material. The device can also comprise epitaxial heterostructures of InAs, GaAs, AISb, and related alloys forming light emitting structures cascaded by tunnel junctions. Further, the device can comprise light emission from the front, epitaxial side of the substrate.