Nanorod LED Structure With Porous Layer for Luminous Efficiency
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Solution Overview
Problem
Miniaturization of light emitting diodes (LEDs) to micro or nano units results in reduced luminous efficiency.
Innovation Solution
A nanorod light emitting device with a nano-scale diameter is developed, featuring a substrate structure with a porous semiconductor layer, a buffer layer, and a passivation film. The device includes a semiconductor light emitting structure with a nanorod shape, a first semiconductor layer doped with an impurity, a light emitting layer with a multi-quantum well structure, and a second semiconductor layer with opposite conductivity type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If LEDs are miniaturized to micro or nano units, then the size of the LED is reduced, but the luminous efficiency is lowered
Solution Approach 1:
The patent employs a porous semiconductor layer containing voids that serve as stress relief regions. This porous structure allows the nanorod LED to accommodate lattice mismatch stress without dislocation, thereby maintaining high luminous efficiency even at nano-scale dimensions. The porous layer is formed between the substrate and the active nanorod structure, providing mechanical compliance while preserving optical performance.
Solution Approach 2:
The patent utilizes a multi-quantum well structure with varying well widths and barrier heights to optimize carrier confinement and recombination efficiency. By adjusting the thickness parameters of the quantum wells and barriers, the device achieves enhanced luminous efficiency despite the reduced overall size. The quantum well parameters are specifically tuned to maintain high radiative recombination rates in the nanorod configuration.
2Volume of moving object
If a nanorod shape is used to maintain nano-scale diameter, then the size is controlled, but additional structural complexity is introduced
Solution Approach 1:
The nanorod LED structure is segmented into distinct functional layers including the porous semiconductor layer, multiple quantum well layers with different compositions, and contact layers. This segmentation allows each layer to be optimized independently for its specific function while maintaining overall compactness. The vertical stacking of these segments achieves precise diameter control through selective etching and growth processes.
Solution Approach 2:
The patent transitions from planar LED structures to vertically-oriented nanorod structures, utilizing the vertical dimension to achieve light emission while maintaining a small footprint diameter. This dimensional change allows the device to overcome the size-efficiency tradeoff by extending the active region vertically rather than horizontally, thereby controlling diameter without sacrificing luminous efficiency.
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 nanorod light emitting device achieves improved luminous efficiency while maintaining a nano-scale diameter, effectively addressing the efficiency loss encountered in miniaturized LEDs.
Implementation Method 1
a porous semiconductor layer disposed on the buffer layer, the porous semiconductor layer having a plurality of voids
Implementation Method 2
a first semiconductor layer disposed on the porous semiconductor layer and doped with an impurity of a first conductivity type, a second semiconductor layer disposed on the light emitting layer and doped with an impurity of a second conductivity type
Implementation Method 3
a light emitting layer disposed on the first semiconductor layer and having a multi-quantum well structure
Data Source
AI summary
Provided is a substrate structure including a substrate, a buffer layer disposed on the substrate, a porous semiconductor layer disposed on the buffer layer, the porous semiconductor layer having a plurality of voids, a plurality of semiconductor light emitting structures disposed on the porous semiconductor layer, the plurality of semiconductor light emitting structures having a nanorod shape extending vertically, and a passivation film disposed on a side wall of each of the plurality of semiconductor light emitting structures, the passivation film having an insulation property.