UV Nitride LED Structure Using Pits for Higher Light Output
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Solution Overview
Problem
Existing nitride semiconductor light-emitting elements, as described in Patent Literature 1, have room for improvement in terms of light output.
Innovation Solution
A nitride semiconductor light-emitting element is designed with an n-type semiconductor layer, an active layer emitting ultraviolet light, an electron blocking layer, and a p-type semiconductor layer, where pits are formed in the active and electron blocking layers, with a pit density on the upper surface of the electron blocking layer ranging from 7.0×10^7 to 1.8×10^9 pits/cm^2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If V-pits are formed in the light-emitting layer to suppress non-luminescent recombination and improve luminous efficiency, then luminous efficiency is improved, but light output is insufficient
Solution Approach 1:
The patent applies local quality by creating pits with specific characteristics (depth, diameter, density) in specific locations (electron blocking layer and active layer) to optimize both luminous efficiency and light output. The pits are not uniformly distributed but positioned to locally enhance electron-hole supply while maintaining overall efficiency.
Solution Approach 2:
The patent changes parameters such as pit density (7.0×10^7 to 1.8×10^9 pits/cm²), pit depth (10 to 60 nm), and pit diameter (20 to 100 nm) to achieve the optimal balance between luminous efficiency and light output. These parameter adjustments allow the structure to simultaneously reduce non-luminescent recombination and enhance light extraction.
2Illumination intensity
If pit density is increased to improve electron hole supply, then light output is enhanced, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines a specific parameter range for pit density (7.0×10^7 to 1.8×10^9 pits/cm²) that balances light output enhancement with manufacturability. This range is wide enough to accommodate normal manufacturing variations while still achieving the desired performance improvement, thereby reducing the stringency of precision requirements.
Solution Approach 2:
The patent accepts that not all pits will be perfectly uniform or precisely positioned, as long as the overall density falls within the specified range. This partial action approach allows for manufacturing tolerance while still achieving the net performance improvement through the collective effect of the pits.
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 configuration enhances light output by facilitating efficient electron hole supply from the p-type semiconductor layer to the active layer through the pits, resulting in improved luminous efficiency.
Implementation Method 1
an active layer being formed on the n-type semiconductor layer and emitting ultraviolet light
Implementation Method 2
pits are formed in the active layer and the electron blocking layer, and wherein a density of the pits on an upper surface of the electron blocking layer is not less than 7.0×10^7 pits/cm^2 and not more than 1.8×10^9 pits/cm^2
Data Source
AI summary
A nitride semiconductor light-emitting element includes an n-type semiconductor layer, an active layer being formed on the n-type semiconductor layer and emitting ultraviolet light, an electron blocking layer formed on the active layer, and a p-type semiconductor layer formed on the electron blocking layer. Pits are formed in the active layer and the electron blocking layer. A density of the pits on an upper surface of the electron blocking layer is not less than 7.0×107 pits/cm2 and not more than 1.8×109 pits/cm2.