AlGaN Heterostructure with Si-Delta Doping for UV LED Conductivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional AlGaN UV light-emitting diodes face challenges in electrical conduction due to increasing donor and acceptor activation energies with Al-composition, leading to deficiencies in free electron and hole carriers, which affects the efficiency and reliability of UV light emission.
Innovation Solution
The design incorporates p-type doped AlGaN layers with strategically placed sheets of positive charge via Si-delta doping, optimizing the distance between charge sheets and Al-composition to enhance dopant activation and carrier confinement, resulting in improved conductivity and quantum confinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If Al-composition in AlGaN layers is increased to improve UV emission wavelength, then emission wavelength is reduced (toward UVC), but donor and acceptor activation energies increase, leading to deficiency of free electron and hole carriers
Solution Approach 1:
The patent applies parameter changes by systematically varying the Al-composition in AlGaN layers to optimize both emission wavelength and electrical conductivity. Specifically, the patent uses AlGaN layers with Al-composition ranging from 0.3 to 0.8, where higher Al-composition (0.6-0.8) is used in regions requiring higher conductivity (such as contact layers and blocking layers), while moderate Al-composition (0.3-0.5) is used in active regions for optimal UV emission. This graded parameter approach resolves the contradiction between wavelength optimization and conductivity maintenance.
Solution Approach 2:
The patent employs composite material structures by combining multiple AlGaN layers with different Al-compositions and doping types (n-type and p-type) to create a heterostructure. The device includes n-type AlGaN layers with Al-composition of 0.3-0.5 for active emission, p-type AlGaN layers with Al-composition of 0.6-0.8 for electron blocking and hole injection, and contact layers with optimized composition for low resistance. This composite approach allows each layer to be optimized for its specific function, resolving the conductivity-wavelength trade-off.
2Strength
If conventional p-type AlGaN layers are used with high Al-composition to improve electron-blockage, then electron blocking capability is enhanced, but hole injection and conductivity are reduced due to high acceptor activation energy
Solution Approach 1:
The patent applies local quality by creating regions with different Al-compositions and doping characteristics tailored to specific functional requirements. The p-type AlGaN layers have Al-composition of 0.6-0.8 specifically in regions where electron blocking is needed (such as the electron blocking layer adjacent to the n-type layer), while the composition is optimized in hole injection regions. This localized optimization allows high electron blocking capability without sacrificing hole injection efficiency, as each region has properties suited to its specific function.
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 enhances the electrical conductivity and reliability of UV LEDs by increasing dopant activation and carrier accumulation, leading to improved light-emission efficiency and reduced electromigration of interstitial hydrogen, thus enhancing the overall performance of UV light-emitting devices.
Implementation Method 1
each of the one or more p-type doped AlGaN layers containing one or more sheets of positive charge inserted therein
Implementation Method 2
enhance dopant activation to improve electrical conductivity
Implementation Method 3
design rules for AlGaN heterostructures of improved conductivity and quantum confinement
Data Source
AI summary
Heterostructures containing one or more sheets of positive charge, or alternately stacked AlGaN barriers and AlGaN wells with specified thickness are provided. Also provided are multiple quantum well structures and p-type contacts. The heterostructures, the multiple quantum well structures and the p-type contacts can be used in light emitting devices and photodetectors.