Graphene Optical Sensor with Topological Insulator
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Solution Overview
Problem
Existing optical sensors in the infrared (IR) region require cooling systems, making them unsuitable for mobile health devices due to large size and low reaction wavelength selectivity and responsivity, particularly with graphene, which lacks selectivity and efficiency.
Innovation Solution
An optical sensor design incorporating a substrate with a topological insulator layer, a graphene layer, and an ion gel dielectric layer, where the topological insulator layer is patterned into a metamaterial unit-cell array and the graphene layer is stacked with an overlapping region, allowing for adjustable Fermi levels and enhanced responsivity through ion gel gating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing optical sensors in the IR region are used, then detection capability is achieved, but system volume increases due to cooling system requirements
Solution Approach 1:
The patent extracts and removes the cooling system from the optical sensor design by using graphene's room-temperature operation capability, keeping only the essential detection components (graphene layer, substrate, electrodes) while eliminating unnecessary thermal management systems
Solution Approach 2:
The patent changes the operating temperature parameter from cryogenic temperatures (requiring cooling systems) to room temperature by utilizing graphene's inherent properties, thereby eliminating the need for complex cooling apparatus and reducing overall system volume
2Ease of manufacture
If graphene is used in optical sensors, then material availability is improved, but reaction wavelength selectivity deteriorates due to consistent response across all wavelengths
Solution Approach 1:
The patent creates a composite structure by combining graphene with specific substrate materials and patterning techniques, where the graphene maintains its manufacturing advantages while the composite structure provides the wavelength selectivity that pure graphene lacks
Solution Approach 2:
The patent segments the graphene layer into specifically patterned regions (such as slit patterns or geometric shapes) that interact with specific wavelengths of light, creating wavelength-dependent responses while maintaining the overall graphene structure for ease of manufacture
3Device complexity
If graphene is used in optical sensors, then material simplicity is maintained, but responsivity deteriorates due to low optical efficiency
Solution Approach 1:
The patent enhances graphene's optical efficiency by utilizing its two-dimensional nature and creating vertical stacking configurations or integrating with other layers in the third dimension, thereby improving light-matter interaction without complicating the fundamental material choice
Solution Approach 2:
The patent introduces intermediary structures or materials (such as dielectric layers, metal contacts, or patterned substrates) that mediate between the incident light and graphene, enhancing the optical coupling and responsivity while keeping the core graphene-based design simple
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 design improves reaction wavelength selectivity and responsivity, enabling effective detection of IR light without a spectrometer, suitable for mobile health devices by tuning resonance absorption within specific IR ranges.
Implementation Method 1
The topological insulator layer may be prepared such that resonance absorption occurs within a range of about 3-4 μm
Implementation Method 2
The graphene Fermi level of the graphene layer may be adjusted by an amount in a range of 1-2 μm through the ion gel layer to tune a resonance absorption location of the topological insulator layer
Implementation Method 3
an optical sensor capable of detecting light of an infrared (IR) region
Data Source
AI summary
An optical sensor is disclosed. The optical sensor may include a substrate, a topological insulator layer formed on the substrate, an oxide layer formed on the topological insulator layer, a graphene layer stacked on the oxide layer, and a dielectric layer covering the graphene layer.