3D Photonic Crystal Light Source for High-Brightness LED
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Solution Overview
Problem
Current light-emitting diodes (LEDs) using group III nitride semiconductors face inefficiencies in the green, yellow, and red wavelengths due to the limitations of two-dimensional photonic crystals, which do not provide complete three-dimensional light control, necessitating the development of a true three-dimensional photonic crystal with a direct bandgap semiconductor for enhanced light emission.
Innovation Solution
A three-dimensional photonic crystal structure comprising a direct bandgap semiconductor with a p-n junction, fabricated using a logpile structure and selective metal organic chemical vapor deposition, featuring a photonic density-of-states that enhances light emission by modifying the electromagnetic environment, allowing for complete control of light emission in the visible spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If two-dimensional photonic crystals are used in LEDs, then fabrication is easier, but complete three-dimensional light control is not achieved
Solution Approach 1:
The patent transitions from two-dimensional photonic crystal structures to three-dimensional photonic crystal structures. The 3DPC is formed by stacking multiple 2DPC layers with alternating orientations, creating a true three-dimensional periodic structure that provides complete photonic bandgap and enables comprehensive light emission control in all spatial dimensions, while maintaining fabrication feasibility through layer-by-layer assembly
2Adaptability or versatility
If three-dimensional photonic crystal structures are implemented, then complete light control is achieved, but device complexity increases
Solution Approach 1:
The three-dimensional photonic crystal is segmented into multiple two-dimensional photonic crystal layers that can be fabricated and assembled separately. Each layer contains periodic patterns of dielectric materials, and the layers are stacked with alternating orientations to form the complete 3D structure. This segmentation enables modular fabrication and simplifies the manufacturing process while achieving the desired three-dimensional light control
Solution Approach 2:
Multiple two-dimensional photonic crystal layers are combined through stacking to form a unified three-dimensional photonic crystal structure. The layers are integrated with an LED chip, where the 3DPC serves as both a light extraction enhancement structure and a wavelength-selective filter, merging multiple functions into a single integrated component
3Adaptability or versatility
If photonic bandgap is created to suppress radiative emission inside the gap, then emission control is improved, but light extraction efficiency in certain wavelengths decreases
Solution Approach 1:
The photonic crystal structure is designed with spatially varying properties to achieve different functions in different regions. The periodic dielectric patterns create photonic bandgaps at specific wavelengths to control unwanted emission, while simultaneously providing enhanced light extraction at desired wavelengths through the photonic density of states modification. This local quality variation enables selective wavelength control without compromising overall light extraction efficiency
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 three-dimensional photonic crystal structure significantly enhances light emission efficiency by creating a photonic bandgap that suppresses radiative emission inside the gap and enhances it outside, achieving high-brightness and scalable light sources with tunable emission wavelengths through defect cavities and phosphor incorporation.
Implementation Method 1
a three-dimensional photonic crystal structure comprising a direct bandgap semiconductor with a p-n junction, fabricated using a logpile structure and selective metal organic chemical vapor deposition, featuring a photonic density-of-states that enhances light emission by modifying the electromagnetic environment
Implementation Method 2
the three-dimensional photonic crystal structure significantly enhances light emission efficiency by creating a photonic bandgap that suppresses radiative emission inside the gap and enhances it outside
Implementation Method 3
at least one p-n junction is located within the three-dimensional photonic crystal; and electrical contacts configured to produce electrical biasing of the at least one p-n junction to provide emission of light by recombination of electrical carriers at the p-n junction
Implementation Method 4
the three-dimensional photonic crystal comprises at least one semiconductor with a direct bandgap wherein at least one p-n junction is located within the three-dimensional photonic crystal
Data Source
AI summary
A volume-scalable, high-brightness, electrically driven visible light source comprises a three-dimensional photonic crystal (3DPC) comprising one or more direct bandgap semiconductors. The improved light emission performance of the invention is achieved based on the enhancement of radiative emission of light emitters placed inside a 3DPC due to the strong modification of the photonic density-of-states engendered by the 3DPC.