Semiconductor Column Core-Shell Structure for White Light Generation
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Solution Overview
Problem
Conventional semiconductor layer sequences for generating visible light face challenges in efficiently coupling primary radiation to conversion materials, particularly in producing high-quality white light with a high color rendering index, due to complex integration of conversion materials and light diffusion issues.
Innovation Solution
A semiconductor layer sequence comprising semiconductor columns with a core-shell structure and a conversion shell that absorbs primary radiation to generate secondary radiation through photoluminescence, allowing for direct application of the conversion shell to the semiconductor layer sequence, enhancing light efficiency and simplifying production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional semiconductor layer sequences are used with separate conversion materials, then white light can be produced, but light efficiency is reduced and production becomes complex
Solution Approach 1:
The conversion material is integrated directly into the semiconductor layer sequence by forming a conversion shell around the semiconductor column, merging the light generation and wavelength conversion functions into a single unified structure. This eliminates the need for separate conversion material layers and improves optical coupling efficiency.
Solution Approach 2:
The conversion shell is formed around the semiconductor column in a nested configuration, where the conversion material surrounds the semiconductor active region. This nested structure enables direct optical coupling while maintaining a compact and integrated device architecture.
2Productivity
If conversion materials are integrated into semiconductor layer sequences, then light efficiency improves, but manufacturing complexity increases
Solution Approach 1:
The conversion shell is formed around the semiconductor column during the epitaxial growth process itself, before final device assembly. This preliminary integration of the conversion material eliminates subsequent complex assembly steps and simplifies the overall manufacturing process.
Solution Approach 2:
The mechanical assembly of separate conversion materials is replaced by epitaxial growth of the conversion shell directly on the semiconductor column. This substitution of growth-based integration for mechanical assembly simplifies manufacturing and improves production efficiency.
3Manufacturing precision
If conversion shells are applied to semiconductor columns, then color rendering index improves, but manufacturing precision requirements increase
Solution Approach 1:
The conversion shell is formed through self-organized epitaxial growth around the semiconductor column, where the growth process automatically conforms to the column geometry. This self-service approach achieves uniform coverage without requiring complex external alignment or application processes.
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 increases light efficiency and simplifies production by enabling effective coupling of primary radiation to conversion materials, achieving high-quality white light with improved color rendering indices and increased luminance without the need for additional luminescent materials.
Implementation Method 1
The active zone is designed to generate primary radiation. The primary radiation is generated by means of electroluminescence, i.e. by charge carrier recombination.
Implementation Method 2
The conversion shell is designed to generate secondary radiation, wherein the secondary radiation is of a longer wavelength than the primary radiation. The secondary radiation is generated from the primary radiation by way of photoluminescence
Data Source
AI summary
In at least one embodiment, the semiconductor layering sequence (1) is designed for generating light and comprises semiconductor columns (2). The semiconductor columns (2) have a respective core (21) made of a semiconductor material of a first conductivity type, and a core shell (23) surrounding the core (21) made of a semiconductor material of a second conductivity type. There is an active zone (22) between the core (21) and the core shell (23) for generating a primary radiation by means of electroluminescence. A respective conversion shell (4) is placed onto the semiconductor columns (2), which conversion shell at least partially interlockingly surrounds the corresponding core shell (23), and which at least partially absorbs the primary radiation and converts same into a secondary radiation of a longer wavelength by means of photoluminescence. The conversion shells (4) which are applied to adjacent semiconductor columns (2), only incompletely fill an intermediate space between the semiconductor columns (2).