Nano-Diamond Composite Substrate for UV-LED Light Extraction
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Solution Overview
Problem
The limited hole injection efficiency of p-type AlGaN layers in UV-LEDs leads to poor light extraction efficiency due to strong absorption and low reflectivity of ultraviolet light, causing heat buildup and reliability issues.
Innovation Solution
A composite substrate with a nano-diamond structure is used, featuring nano-diamond protrusions and gaps, which allows for the growth of semiconductor layers with improved conductive properties and light reflection, reducing UV light absorption and enhancing light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If p-GaN layer is used to improve hole injection efficiency, then hole injection efficiency is improved, but light extraction efficiency deteriorates due to strong UV light absorption
Solution Approach 1:
The patent extracts the problematic p-GaN layer from the device structure and replaces it with a p-type AlOxGaN layer. This removal of the light-absorbing p-GaN layer while maintaining hole injection functionality through the alternative p-type AlOxGaN material resolves the contradiction between hole injection efficiency and light extraction efficiency.
Solution Approach 2:
The patent changes the material composition parameter from p-GaN to p-type AlOxGaN, which has different optical properties. The AlOxGaN material maintains the necessary electrical properties for hole injection while having reduced UV light absorption, thereby resolving the contradiction through material parameter modification.
2Reliability
If p-GaN layer is used to make p-type ohmic contacts, then hole injection efficiency is improved, but device temperature rises due to heat generation from absorbed light
Solution Approach 1:
The patent removes the heat-generating p-GaN layer from the structure and replaces it with p-type AlOxGaN material that does not strongly absorb UV light. This extraction eliminates the source of heat generation while preserving the hole injection function, thereby resolving the contradiction between hole injection efficiency and device temperature control.
3Ease of manufacture
If conventional substrate is used, then manufacturing is simple, but light extraction efficiency is low due to UV light absorption
Solution Approach 1:
The patent employs a composite substrate structure consisting of sapphire substrate, AlN buffer layer, and p-type AlOxGaN layer. This composite structure combines the manufacturing advantages of sapphire with the optical and electrical benefits of AlN and AlOxGaN, achieving both ease of manufacture and high light extraction efficiency by preventing UV light absorption.
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 nano-diamond structure effectively increases light extraction efficiency and reduces heat dissipation issues, improving the performance and reliability of UV-LEDs by minimizing UV light absorption and enhancing electron reflection.
Implementation Method 1
enhancing electron reflection
Implementation Method 2
minimizing UV light absorption
Data Source
AI summary
A composite substrate, a photoelectric device and a preparation method therefor. The composite substrate comprises a base substrate and a nano-diamond structure located on the base substrate; the nano-diamond structure comprises a plurality of nano-diamond protrusions arranged at intervals, and a gap is provided between two adjacent nano-diamond protrusions. The photoelectric device comprises the composite substrate, and further comprises a first semiconductor layer, an active layer, and a second semiconductor layer stacked on the composite substrate; the first semiconductor layer comprises protruding portions and a flat portion sequentially stacked in the vertical direction, the protruding portions are in the gaps and correspond one-to-one to the gaps, and the flat portion is located on the protruding portions and the nano-diamond structure. The preparation method for the photoelectric device is used for manufacturing the photoelectric device.