UV-LED Chip Al Composition for Efficiency
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Solution Overview
Problem
Current UV-LED chips face limitations in luminous efficiency and power output decrease with increasing current density, particularly in micro LED displays where chip size and wavelength optimization are crucial for improving performance.
Innovation Solution
The UV-LED chip design optimizes wavelength and chip size by stacking specific layers such as u-GaN buffer layers, (GaN;Si) n-contact layers, (InGaN/AlGaN) multiple quantum well light emitting layers, and p-AlGaN;Mg layers on a sapphire substrate, with the inclusion of an (AlInGaN)/(InGaN;Si) n-superlattice structure and p-GaN layers, and using remote plasma deposition and plasma-enhanced chemical vapor deposition techniques to enhance luminous efficiency and reduce power output decrease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If UV-LED chips are used to excite phosphors in displays, then color reproducibility and excitation efficiency are improved, but luminous efficiency remains insufficient
Solution Approach 1:
The patent optimizes the Al composition ratio distribution across different layers (undoped layer has smallest ratio, increasing toward contact layer and electron blocking layer) to control carrier concentration and improve luminous efficiency while maintaining excitation performance
Solution Approach 2:
The patent uses composite AlGaN structures combining undoped, n-type, and p-type layers with different Al composition ratios to achieve both high excitation efficiency and improved luminous efficiency through optimized carrier management
2Power
If current density is increased to improve output, then power output increases, but rate of power output decrease accelerates
Solution Approach 1:
The patent creates different Al composition ratios in different layers (undoped, n-type, p-type contact, electron blocking) to locally optimize carrier concentration and reduce non-radiative recombination, thereby reducing the rate of power output decrease at high current densities
Solution Approach 2:
The undoped AlGaN layer acts as an intermediary between the substrate and doped layers, providing a transition zone that manages carrier distribution and reduces power output degradation at high current densities
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 approach significantly improves luminous intensity and efficiency, particularly in micro-sized chips with emission wavelengths of 385 nm and 400 nm, reducing power output decrease with current density and enhancing internal quantum efficiency and light extraction efficiency.
Implementation Method 1
using remote plasma deposition and plasma-enhanced chemical vapor deposition techniques to enhance luminous efficiency
Implementation Method 2
UV-LED chips having an emission wavelength of 385 nm or 400 nm
Implementation Method 3
an (InGaN/AlGaN) multiple quantum well light emitting layer
Data Source
Figure 1A~1B(c)
Figure 2~3
Figure 4~5
AI summary
A UV-LED is disclosed. The UV-LED includes a patterned sapphire substrate 20, a u-GaN buffer layer 22 formed on the sapphire substrate 20, an n-GaN contact layer 24 formed on the u-GaN buffer layer 22, an InGaN light emitting layer 28 formed on the n-GaN contact layer 24, and a p-GaN layer 30 formed on the InGaN light emitting layer 28. The UV-LED has a quadrate planar shape with at least one side having a chip size of 50 µm or less.