Nitride Semiconductor Light Emitting Element With Graded Exciton Localization
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Solution Overview
Problem
Current semiconductor light emitting elements, particularly those using Group III-V nitride compounds, face inefficiencies due to high non-radiative recombination rates caused by defects and carrier density variations, which affect luminous efficiency and internal quantum efficiency.
Innovation Solution
The semiconductor light emitting element is designed with a structure that includes a first p-side well layer with a lower localization energy for excitons and a second p-side well layer with a higher localization energy, alternately stacked with barrier layers, to optimize carrier density and reduce non-radiative recombination, enhancing luminous efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional uniform well layer structure is used, then the manufacturing process is simple, but non-radiative recombination occurs due to carrier density variations and defects, reducing luminous efficiency
Solution Approach 1:
The patent applies local quality by creating well layers with different localization energies at different positions. Specifically, the well layer adjacent to the p-type semiconductor layer has a first localization energy, while other well layers have a second localization energy different from the first. This spatial variation in localization energy optimizes carrier confinement and reduces non-radiative recombination at defect-prone regions, directly addressing the energy loss problem while maintaining a relatively simple overall structure.
2Illumination intensity
If carrier density is increased to improve light emission, then luminous efficiency may improve, but non-radiative recombination increases due to defects and carrier density variations
Solution Approach 1:
The patent employs parameter changes by varying the localization energy parameter across different well layers. The first well layer adjacent to the p-type semiconductor layer is designed with a specific localization energy, while subsequent well layers have different localization energies. This parameter variation allows optimization of carrier distribution and recombination characteristics, enabling high light emission intensity while maintaining high internal quantum efficiency by reducing non-radiative recombination pathways.
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 increases luminous efficiency by suppressing non-radiative recombination and improving internal quantum efficiency, leading to a more efficient light emitting diode (LED) with improved performance across varying carrier densities.
Implementation Method 1
a light emitting unit. The light emitting unit includes a plurality of well layers stacked alternately with a plurality of barrier layers
Implementation Method 2
Group III-V nitride compound semiconductors such as gallium nitride (GaN) and the like are being applied to semiconductor light emitting elements such as light emitting diodes (LEDs)
Data Source
AI summary
According to one embodiment, a semiconductor light emitting element includes a first semiconductor layer of an n-type, a second semiconductor layer of a p-type, and a light emitting unit. The first semiconductor layer includes a nitride semiconductor. The second semiconductor layer includes a nitride semiconductor. The light emitting unit is provided between the first semiconductor layer and the second semiconductor layer. The light emitting unit includes a plurality of well layers stacked alternately with a plurality of barrier layers. The well layers include a first p-side well layer most proximal to the second semiconductor layer, and a second p-side well layer second most proximal to the second semiconductor layer. A localization energy of excitons of the first p-side well layer is smaller than a localization energy of excitons of the second p-side well layer.