Far-UVC MicroLED Sidewall Extraction for Contact Loss Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional far-UVC light sources face challenges in efficiency and reliability due to difficulties in light extraction and directionality, particularly with solid-state LEDs, which have short operating lifetimes and poor performance at wavelengths below 265 nm, and macroscopic LEDs struggle with optical transparency and contact absorption issues.
Innovation Solution
The development of microscale LEDs (microLEDs) with reduced lateral dimensions and optimized sidewalls for light extraction, allowing for improved light directionality and efficiency by shortening the optical path length and decoupling electrical contacts from light extraction surfaces, using AlGaN semiconductor materials and optical redirection structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solid-state LEDs are used for far-UVC light generation, then device compactness and reliability are improved, but light extraction efficiency and operating lifetime deteriorate due to short wavelengths below 265 nm
Solution Approach 1:
The patent transitions from conventional planar LED structures to vertically stacked three-dimensional architectures. Multiple active regions are stacked along the vertical dimension, enabling independent optimization of each layer's light extraction path while maintaining compact footprint. This dimensional transition allows photons to escape through multiple surfaces (top, bottom, and sidewalls) rather than being constrained to a single plane, thereby improving overall light extraction efficiency without sacrificing reliability.
Solution Approach 2:
The LED structure is segmented into multiple discrete active regions stacked vertically, with each segment capable of independent light emission. The device is divided into distinct functional layers including n-type contact regions, active regions with quantum wells, p-type contact regions, and dedicated light extraction surfaces. This segmentation allows each component to be optimized for its specific function, improving both light extraction efficiency and operational reliability.
2Ease of manufacture
If macroscopic LED structures are used, then manufacturing simplicity is maintained, but optical transparency and contact absorption issues worsen light extraction
Solution Approach 1:
The patent employs vertical stacking to separate electrical contact functions from light extraction functions in the vertical dimension. Electrical contacts are positioned at the top and bottom surfaces, while light extraction occurs through dedicated sidewall surfaces and additional top/bottom extraction layers. This dimensional separation allows macroscopic structures to maintain manufacturing simplicity while minimizing contact absorption, as the electrical contacts do not block the primary light extraction paths.
Solution Approach 2:
The patent extracts the light extraction function from the conventional top surface only and creates dedicated light extraction surfaces including sidewalls and additional top/bottom layers. This extraction of the light extraction function to separate locations allows electrical contacts to be positioned without blocking light paths, thereby reducing contact absorption losses while maintaining macroscopic structural simplicity for ease of manufacture.
3Ease of manufacture
If conventional planar LED structures are used, then fabrication processes are simplified, but light directionality and extraction efficiency deteriorate
Solution Approach 1:
The patent adds vertical stacking to the conventional planar structure, creating multiple active regions at different vertical levels. Each stacked layer provides additional light extraction surfaces, effectively multiplying the light extraction efficiency without complicating the horizontal fabrication processes. The vertical dimension is added through sequential epitaxial growth, which maintains fabrication simplicity while dramatically improving light extraction productivity.
Solution Approach 2:
The patent implements nested functional layers within the vertical structure, where multiple active regions are nested along the vertical axis. Each nested layer contains quantum wells and active regions that contribute to light emission, and the nested arrangement allows light to be extracted through multiple surfaces simultaneously. This nesting approach increases light extraction efficiency while using standard sequential fabrication processes.
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
MicroLEDs enhance light extraction efficiency and reduce electrical resistance, achieving higher quantum efficiency and power output suitable for germicidal applications while ensuring human safety.
Implementation Method 1
a light emitting diode (LED) includes a semiconductor structure comprising at least one epitaxial layer that is configured to generate far-UVC light
Implementation Method 2
the at least one sidewall is configured to direct the far-UVC light into a beam or into a distributed pattern
Data Source
AI summary
A light emitting diode (LED) includes a semiconductor structure comprising at least one epitaxial layer that is configured to generate far-UVC light, and respective electrical contacts on first and second surfaces of the semiconductor structure. One or more dimensions of the at least one epitaxial layer in a lateral direction are within an order of magnitude of a thickness of the at least one epitaxial layer in a vertical direction. A primary light extraction surface may include at least one sidewall of the semiconductor structure that extends between the first and second surfaces and is configured to emit the far-UVC light. Related devices, arrays thereof, and fabrication methods are also discussed.