SERS Substrate with Multilayer Pillar Hot Spots
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Solution Overview
Problem
Existing methods for manufacturing substrates for surface-enhanced Raman scattering (SERS) are complex, expensive, and limited in producing substrates with high densities of hot spots, resulting in insufficient enhancement of the Raman signal intensity.
Innovation Solution
A method involving the production of a substrate with a microstructured pattern, a multilayer of dielectric materials, and selective etching to form cavities and metal pins, enhancing the electromagnetic field and creating a high density of hot spots for increased Raman signal intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prior art structuring technologies are used to form hot spots, then hot spots can be formed on the substrate surface, but the manufacturing process becomes complex and expensive
Solution Approach 1:
The substrate is divided into multiple unit structures, each containing micro-pillars arranged in a periodic pattern. This segmentation allows the complex hot spot formation to be achieved through simple, repetitive fabrication steps rather than complex monolithic structuring.
Solution Approach 2:
A dielectric layer is introduced as an intermediary material between the substrate and the metal layers. This dielectric layer with refractive index n=3.5 serves as a mediator to control electromagnetic field distribution and enable hot spot formation through a simple planar fabrication process.
2Reliability
If prior art methods are used to form hot spots, then some enhancement can be achieved, but the density of hot spots remains limited
Solution Approach 1:
The substrate surface is segmented into numerous identical unit structures arranged in a periodic array. Each unit structure contains multiple micro-pillars that generate hot spots, and the periodic arrangement ensures high spatial density of these hot spots across the entire substrate surface.
Solution Approach 2:
The electromagnetic response of the substrate is tuned by adjusting the geometric parameters of the unit structures, including the size, spacing, and arrangement of micro-pillars. The dielectric layer thickness and refractive index are also optimized to achieve resonance conditions that maximize hot spot density and intensity.
3Manufacturing precision
If high spatial resolution structuring technologies are used, then precise hot spot positions can be achieved, but the production cost increases significantly
Solution Approach 1:
The precise positioning requirement is relaxed by segmenting the substrate into periodic unit structures. The periodicity provides self-alignment and ensures consistent hot spot positions without requiring high-precision lithography, as the structures are defined by simple repeating patterns that can be fabricated with standard techniques.
Solution Approach 2:
Identical unit structures are copied and arranged in a periodic array across the substrate. This copying approach ensures uniform hot spot characteristics throughout the substrate while using simple, low-cost fabrication processes. The repetitive nature of the pattern allows for mass production with consistent 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 method allows for a significant enhancement of the Raman signal intensity, enabling faster detection of molecules with a simpler, more reproducible, and cost-effective process, capable of producing multiple identical substrates with enhanced electromagnetic field reinforcement.
Implementation Method 1
This is achieved through the excitation of localized plasmons in the metal (electromagnetic enhancement)
Implementation Method 2
through charge transfer between the metal and the adsorbed molecule (chemical enhancement)
Implementation Method 3
These hotspots are areas of the substrate where the electromagnetic field is localized and intense
Data Source
Figure 1a~1d
Figure 1e~1g
Figure 1c'~1e'
AI summary
The invention relates to a Surface Enhanced Raman Scattering Substrate comprising: - a support (3) having a top surface (4); - a load-bearing structure (2) having at least one microstructured pattern (5), the microstructured pattern (5) having a vertex (8) and lateral walls (7), the lateral walls (7) extending in a direction secant to the direction of the top surface (4); - a multilayer (10) arranged on the lateral walls (7) of the microstructured pattern (5), the multilayer (10) comprising at least two pillar layers (13), separated from each other by an interlayer (14), each interlayer (14) having an end (18) set back from an end (19) of each adjacent pillar layer (13) so that the ends (19) of two successive pillar layers (13) form bumps separated by a cavity (20), the ends (19) of the pillar layers (13) being covered by a metallic layer (40);- the carrier structure: o being dimensioned so as to form a photonic crystal with respect to an incident wave illuminating the substrate and/or o being such that the lateral walls (7) of the microstructured pattern have faces (11) separated from each other by edges (12), the angle of these edges (12) being chosen so that the carrier structure, once covered by the multilayer (10), generates a reinforcement of the electromagnetic field by point effect in areas (28) located near the edges (12).;