Full-Color Nitride Micro-LED Array with One-Step Monolithic Integration
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Solution Overview
Problem
Current methods for preparing full-color micro-LEDs face challenges such as large device size due to electrode processing requirements, low electro-optical conversion efficiency, and material incompatibility issues between nitride and phosphide semiconductors, as well as between semiconductors and organic quantum dots, leading to complex, energy-inefficient, and low-yield processes.
Innovation Solution
A method for monolithic integration preparation of a full-color nitride semiconductor micro-LED array involves preparing a composite conductive substrate, using an insulating template to define pixel regions, and growing vertical-structure all-nitride materials on a customized template graphene substrate through a one-step in-situ process, enabling top light emission and overcoming material compatibility issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If massive transfer technology is used to prepare full-color micro-LEDs, then red-green-blue full-color display is achieved, but device size must be larger than 10 μm resulting in low electro-optical conversion efficiency
Solution Approach 1:
The device is segmented into functionally independent regions: a nitride semiconductor region for UV/blue light emission and a phosphide semiconductor region for red light emission. Each region operates independently with optimized dimensions, allowing the red-emitting region to be smaller than 10 μm while maintaining reliability, thus improving electro-optical conversion efficiency while achieving full-color display
Solution Approach 2:
Different regions of the light-emitting device are assigned different material compositions and structural characteristics. The nitride region uses AlInGaN with specific aluminum content for UV/blue emission, while the phosphide region uses AlInGaP for red emission. Each region has locally optimized properties including doping concentrations, layer thicknesses, and crystal structures matched to its specific emission wavelength requirements
2Ease of manufacture
If monolithic integration based on quantum dot deposition is used, then red-green-blue full-color display is achieved, but material incompatibility between nitride and phosphide makes the process complex and low-yield
Solution Approach 1:
The monolithic integration approach segments the device into separate nitride and phosphide semiconductor regions that are epitaxially grown on different substrate orientations. This segmentation allows each material system to be optimized independently while maintaining material compatibility, avoiding the complex quantum dot deposition processes and achieving high-yield full-color display
Solution Approach 2:
The device employs a composite material structure combining nitride semiconductor (AlInGaN) and phosphide semiconductor (AlInGaP) in a monolithic integration. The nitride region provides UV/blue emission while the phosphide region provides red emission. The composite structure leverages the complementary properties of both material systems to achieve full-color display with high efficiency and simplified processing
3Reliability
If conventional electrode processing is used, then reliable electrical connection is achieved, but device size must be larger than 10 μm reducing light efficiency
Solution Approach 1:
The electrode structure is segmented into separate contact regions for n-type and p-type electrodes, with each contact independently optimized. The p-type contact in the red-emitting region can be smaller than 10 μm since it only needs to serve that specific region, while maintaining reliable electrical connection. This segmentation allows reduced device size and improved light efficiency without sacrificing electrode reliability
Solution Approach 2:
An intermediate layer or structure is introduced between the electrode and the active region to enable reliable electrical connection in smaller devices. This intermediary element facilitates efficient charge transport while allowing the overall device footprint to be reduced below the conventional 10 μm limit, thereby improving light 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
This method allows for the efficient, energy-saving, and environmentally friendly production of small-sized, high-light-efficiency full-color micro-LED arrays with top light emission, suitable for mass production and applications in virtual and augmented reality.
Implementation Method 1
attaching the n-type conductive monocrystalline silicon wafer onto the transparent insulating substrate
Implementation Method 2
attaching the n-type conductive monocrystalline silicon wafer onto the transparent insulating substrate
Implementation Method 3
using an insulating template to define pixel regions
Implementation Method 4
growing vertical-structure all-nitride materials on a customized template graphene substrate
Implementation Method 5
one-step in-situ process, enabling top light emission
Data Source
AI summary
Disclosed is a method for monolithic integration preparation of a full-color nitride semiconductor micro light-emitting diode (micro-LED) array. The method includes preparing a composite conductive substrate; overlaying an insulating template onto the composite conductive substrate to prepare a template substrate; overlaying monocrystalline graphene onto the template substrate in a completely aligned manner to obtain a customized template graphene substrate including graphene array units, wherein one blue-region graphene array element, one green-region graphene array element, and two red-region graphene array elements in each graphene array unit have surface properties different from each other; then performing an in-situ process to epitaxially grow a vertical-structure all-nitride material, to obtain a full-color micro-LED array epitaxial wafer by one-step in-situ process; finally, performing packaging and preparing a transparent electrode, to obtain a vertical-structure full-color nitride micro-LED array with top light emission.