Flexible Graphene Sheet Transfer Without Wrinkling or Contamination
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Solution Overview
Problem
Existing methods for transferring graphene from growth substrates to other surfaces often result in wrinkling, contamination, and degradation of its electrical properties due to the use of thin polymer layers and subsequent patterning processes.
Innovation Solution
A method involving growing pristine monolayer graphene on a catalytic film, attaching a rigid first layer of material, and using a bubbling transfer process to release it, ensuring high electronic and structural quality, with optional additional layers for structural support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If graphene is coated with a thin polymer layer (PMMA) for transfer, then mechanical stability is improved, but the graphene becomes wrinkled and contaminated during the transfer process
Solution Approach 1:
The patent uses a thick polymer layer (1-100 micrometers, preferably 10-50 micrometers) as an intermediary support during transfer, which is significantly thicker than conventional PMMA coatings. This thick polymer layer acts as a mediator that provides sufficient mechanical stability to prevent wrinkling while allowing clean release from the growth substrate without contaminating the graphene.
Solution Approach 2:
The patent changes the thickness parameter of the polymer layer from the conventional thin coating (nanometer scale) to a thick layer (1-100 micrometers). This parameter change fundamentally alters the mechanical properties of the support structure, providing rigidity to prevent graphene wrinkling while maintaining flexibility for transfer operations.
2Ease of manufacture
If conventional transfer methods are used with thin polymer layers, then the transfer process is simple, but the graphene carrier mobility degrades due to wrinkling and contamination
Solution Approach 1:
By changing the polymer layer thickness from nanometer to micrometer scale, the patent simultaneously achieves mechanical stability to preserve electrical properties and maintains process simplicity. The thick polymer layer can be applied using standard spin-coating techniques, requiring no additional process steps.
3Ease of manufacture
If subsequent patterning processes are performed on transferred graphene, then device fabrication is enabled, but chemical contamination occurs exposing the graphene to harmful chemicals
Solution Approach 1:
The patent performs the transfer operation first with the thick polymer support, achieving wrinkle-free and contamination-free graphene placement before any patterning steps. This preliminary transfer with enhanced mechanical support prevents the need for protective measures during subsequent chemical patterning 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
Preserves the high mobility and structural integrity of graphene during transfer, enabling its use in flexible electronics and other applications without degrading its electrical properties.
Implementation Method 1
releasing the graphene from the catalytic film
Data Source
AI summary
The present invention provides methods for fabricating graphene workpieces. The present invention also provides for products produced by the methods of the present invention and for apparatuses used to perform the methods of the present invention.