Quantum Dot Multilayer Insulator Coating via ALD
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Solution Overview
Problem
Atomic Layer Deposition (ALD) processes on individual metal-oxide coated quantum dots have not been previously attempted, and existing coatings are insufficient to protect quantum dots from environmental and operational stresses, leading to issues like self-quenching and thermal instability.
Innovation Solution
A semiconductor structure is fabricated with a nanocrystalline core and shell, encapsulated by an insulator layer, which is further coated with an additional metal oxide layer using the ALD process, enhancing protection and thermal stability through conformal coverage and multilayer encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single insulator layer is formed around quantum dots, then basic encapsulation is achieved, but protection against environmental stresses and self-quenching is insufficient
Solution Approach 1:
The patent applies nesting by forming multiple insulator layers around the quantum dot core, with each layer encapsulating the previous one. This creates a nested structure where the quantum dot is protected by successive insulator layers, each providing additional protection against environmental stresses and preventing self-quenching effects.
Solution Approach 2:
The patent uses composite materials by combining the quantum dot core with multiple insulator layers formed through different processes (wet chemical processes followed by ALD). This composite structure integrates the optical properties of the quantum dot with the protective properties of the insulator layers, achieving both functionality and protection.
2Adaptability or versatility
If quantum dots are used in demanding applications like LED and solar devices, then application versatility is improved, but thermal stability becomes insufficient
Solution Approach 1:
The patent applies beforehand cushioning by forming insulator layers around the quantum dots before they are subjected to demanding operating conditions. These insulator layers act as a protective cushion that prevents thermal degradation and maintains stability during operation in LED and solar devices.
Solution Approach 2:
The patent changes physical parameters by using ALD to precisely control the thickness and composition of insulator layers. This allows optimization of thermal properties while maintaining protection, enabling the quantum dots to withstand higher temperatures in demanding applications.
3Manufacturing precision
If ALD process is applied to metal-oxide coated quantum dots, then manufacturing precision is improved, but process complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the coating process into distinct stages: first forming an insulator layer through wet chemical processes, then applying additional insulator layers through ALD. This segmentation allows each process to be optimized independently, achieving high manufacturing precision while managing overall process complexity.
Solution Approach 2:
The patent uses preliminary action by preparing the quantum dots with an initial insulator layer through wet chemical processes before subjecting them to ALD. This preliminary coating provides a foundation that enables the subsequent ALD process to achieve precise and uniform additional coating, improving overall manufacturing precision.
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 additional ALD coating significantly improves the robustness and thermal stability of quantum dots, preventing self-quenching and environmental damage, enabling their use in demanding applications like LED and solar devices.
Implementation Method 1
The quantum dot thus coated is further coated with an additional insulator layer using an Atomic Layer Deposition (ALD) process
Data Source
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AI summary
Fabricating a semiconductor structure including forming a nanocrystalline core from a first semiconductor material, forming a nanocrystalline shell from a second, different, semiconductor material that at least partially surrounds the nanocrystalline core, wherein the nanocrystalline core and the nanocrystalline shell form a quantum dot. Fabrication further involves forming an insulator layer encapsulating the quantum dot to create a coated quantum dot, and forming an additional insulator layer on the coated quantum dot using an Atomic Layer Deposition (ALD) process.