Porous Quantum Dot LED Structure for Surface Defect Losses
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Solution Overview
Problem
Miniaturization of LEDs to micro or nano units leads to reduced luminous efficiency due to surface defects.
Innovation Solution
A light emitting device with a semiconductor light emitting structure that includes a first semiconductor layer with pores, a light emitting layer, a second semiconductor layer, quantum dots within the pores, and passivation layers to enhance luminous efficiency and wavelength selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If LEDs are miniaturized to micro units or nano units, then the size of the light emitting device is reduced, but the luminous efficiency is reduced due to surface defects
Solution Approach 1:
The first semiconductor layer is configured with a porous structure containing multiple pores. Quantum dots are positioned within these pores, allowing the light emitting layer to contact both the semiconductor layer and quantum dots. This porous configuration increases the surface area for light emission while maintaining structural integrity, thereby improving luminous efficiency in miniaturized devices.
Solution Approach 2:
An internal passivation layer is introduced as an intermediary between the first semiconductor layer and the quantum dots. This passivation layer has a greater energy band gap than the semiconductor layer, effectively passivating surface defects and reducing non-radiative recombination. This mediator layer protects the quantum dots from direct contact with defective semiconductor surfaces while maintaining optical coupling.
2Adaptability or versatility
If quantum dots are introduced to convert wavelength, then the light emitting device can emit different wavelengths, but the device structure becomes more complex
Solution Approach 1:
The patent combines multiple functions into a single integrated structure: the first semiconductor layer provides both structural support and light emission, the pores within it accommodate quantum dots for wavelength conversion, and the internal passivation layer simultaneously passivates defects and provides structural continuity. This merging of functions reduces overall device complexity compared to separate components.
Solution Approach 2:
The structure employs a nested configuration where quantum dots are positioned within pores of the first semiconductor layer, which itself is nested within the larger light emitting device structure. The internal passivation layer is nested between the semiconductor layer and quantum dots. This nesting approach maximizes space utilization and simplifies the overall device architecture.
3Loss of energy
If an internal passivation layer is added to surround the semiconductor light emitting structure, then surface defects are reduced and luminous efficiency is improved, but the device complexity increases
Solution Approach 1:
The first semiconductor layer maintains its porous configuration, allowing the internal passivation layer to conformally coat the pore surfaces. This porous structure provides a high surface-area-to-volume ratio, enabling effective passivation of surface defects throughout the entire semiconductor layer while using a relatively thin passivation layer, thus minimizing added complexity.
Solution Approach 2:
The device creates a composite structure combining the semiconductor material with the passivation layer material, which has different optical and electrical properties. This composite approach allows the passivation layer to specifically address surface defect issues while the bulk semiconductor material maintains its light emission functionality, optimizing performance without excessive complexity.
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 solution improves luminous efficiency and enables the emission of light at a wavelength different from the light generated in the light emitting layer, effectively addressing the surface defect issue in miniaturized LEDs.
Implementation Method 1
the plurality of quantum dots are configured to absorb the first light of the first wavelength and emit second light of a second wavelength that is longer than the first wavelength
Implementation Method 2
An internal passivation layer may be provided to surround the sidewall of the semiconductor light emitting structure... the internal passivation layer and the external passivation layer may be configured as a wavelength selective transmission layer
Implementation Method 3
The internal passivation layer and the external passivation layer may be configured as a wavelength selective transmission layer that selectively reflects the first light and selectively transmits the second light
Data Source
AI summary
A light emitting device includes a semiconductor light emitting structure including, a first semiconductor layer including a plurality of pores, a light emitting layer provided on the first semiconductor layer, and a second semiconductor layer provided on the light emitting layer, a plurality of quantum dots provided in the plurality of pores, and an external passivation layer at least partially surrounding a sidewall of the semiconductor light emitting structure, where the plurality of quantum dots are provided between the plurality of pores and the external passivation layer.