Multi-Layered Solid-State Light Emitter Structure
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Solution Overview
Problem
Existing methods for producing silicon nano-particle-based light emitting devices face challenges such as low concentration of rare earth elements, non-uniform distribution, limited film thickness, and reduced efficiency due to ion implantation and deposition techniques, which result in poor surface uniformity and limited light generation capabilities.
Innovation Solution
A multi-layered engineered structure with wide bandgap semiconductor or dielectric buffer layers adjacent to thin active luminescent layers, designed to provide precise energy transfer for efficient light emission, using plasma enhanced chemical vapor deposition and other deposition methods to control nano-particle size and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ion implantation and high temperature annealing are used to produce silicon nano-particles doped with rare earth elements, then rare earth luminescence can be achieved, but the concentration of rare earth elements remains very low and surface uniformity deteriorates
Solution Approach 1:
The device is divided into multiple thin layers (active layers and buffer layers) stacked in sequence. Each active layer contains silicon nano-particles doped with rare earth elements and has a thickness of 1-10 nm. This segmentation allows for higher rare earth concentration in each layer while maintaining uniformity through the multi-layer structure, resolving the contradiction between achieving sufficient rare earth concentration and maintaining surface uniformity.
Solution Approach 2:
The invention transitions from a single-layer structure to a multi-layer stacked structure, adding the dimension of layer stacking. By distributing rare earth-doped active layers throughout the multi-layer structure rather than attempting to achieve high concentration in a single layer, the invention achieves both high effective rare earth concentration and maintained surface uniformity across each individual layer.
2Reliability
If ion implantation is used to dope silicon oxide with rare earth ions, then rare earth luminescence can be activated, but surface uniformity and distribution uniformity deteriorate
Solution Approach 1:
The structure is segmented into multiple thin active layers separated by buffer layers. Each active layer is thin enough (1-10 nm) to maintain uniform rare earth distribution through deposition processes, avoiding the surface uniformity deterioration that occurs with ion implantation in thicker layers. The segmentation allows luminescence activation in each layer while preserving overall surface uniformity.
Solution Approach 2:
Buffer layers composed of silicon oxide or silicon nitride serve as intermediaries between active layers. These buffer layers provide a uniform substrate for depositing subsequent active layers, ensuring that each active layer maintains good surface uniformity and rare earth distribution. The buffer layers mediate between the requirements of luminescence activation and surface uniformity maintenance.
3Reliability
If single-layer structures are used with high rare earth concentration, then luminescence efficiency improves, but surface uniformity and distribution uniformity worsen
Solution Approach 1:
The single-layer structure is segmented into multiple thin layers, each containing a moderate concentration of rare earth elements. While each individual layer has lower rare earth concentration than a hypothetical high-concentration single layer, the cumulative effect of multiple layers provides sufficient total luminescence efficiency. Meanwhile, each thin layer maintains good distribution uniformity, resolving the contradiction between luminescence efficiency and distribution uniformity.
Solution Approach 2:
Each active layer is designed with specific local properties (thin thickness, controlled rare earth concentration) optimized for uniform deposition, while the overall multi-layer structure achieves the required total luminescence efficiency. Different layers can have identical or varied compositions, allowing local optimization for uniformity while achieving global efficiency targets.
4Reliability
If limited film thickness is used in ion implantation processes, then ion implantation damage can be reduced, but the quantity of rare earth elements and luminescence output are limited
Solution Approach 1:
The structure is segmented into multiple thin active layers separated by buffer layers. Each thin active layer (1-10 nm) can be deposited without significant ion implantation damage, maintaining high material quality. The cumulative luminescence output from multiple layers compensates for the limited thickness of each individual layer, resolving the contradiction between reducing ion damage and achieving sufficient luminescence output.
Solution Approach 2:
The invention adds the dimension of layer stacking to overcome the film thickness limitation. Instead of attempting to deposit a single thick layer that would suffer from ion implantation damage and limited output, multiple thin layers are stacked to achieve both damage reduction and sufficient total luminescence output through the cumulative effect of multiple layers.
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 enhances luminous flux, efficiency, color rendering index, device reliability, and manufacturability, allowing for higher concentration of rare earth elements and improved energy transfer, resulting in more effective light generation and longer device lifetime.
Implementation Method 1
electrons gains sufficient energy from the electric field when passing through the first buffer layer to excite the luminescent centers in the first active layer via impact ionization or impact excitation
Implementation Method 2
electrons gains sufficient energy from the electric field when passing through the first buffer layer to excite the luminescent centers in the first active layer via impact ionization or impact excitation
Implementation Method 3
first active layer including a concentration of luminescent centers for emitting light at a first wavelength
Implementation Method 4
using plasma enhanced chemical vapor deposition and other deposition methods to control nano-particle size and distribution
Data Source
AI summary
An engineered structure of a light emitting device comprises multiple layers of alternating active and buffer materials disposed between AC or DC electrodes, which generate an electric field. The active layers comprise luminescent centers, e.g. group IV semiconductor nanocrystals, in a host matrix, e.g. a wide bandgap semiconductor or dielectric material such as silicon dioxide or silicon nitride. The buffer layers are comprised of a wide bandgap semiconductor or dielectric material, and designed with a thickness, in the direction of an applied electric field, that ensures that electrons passing therethrough picks up enough energy to excite the luminescent centers in the adjacent active layer at an excitation energy to emit light efficiently at a desired wavelength.