High Purity Copper Foil for Large Area Graphene CVD Growth
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Solution Overview
Problem
Current methods for producing graphene face challenges in achieving uniformity and large area coverage due to the high cost and limited size of monocrystal metal substrates, and copper foils with high oxygen concentrations result in increased sheet resistance and poor graphene quality.
Innovation Solution
A copper foil with a purity of 99.95% to 99.995% and an oxygen concentration of 200 ppm or less is used, with a smooth surface and controlled crystal grain size, to facilitate the growth of large area graphene through CVD, ensuring uniform catalyst function and reducing impurity effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a monocrystal metal substrate is used for graphene production, then the quality and uniformity of graphene are improved, but the cost increases and the area is limited
Solution Approach 1:
The patent replaces expensive monocrystal metal substrates with ordinary copper foils that have limited service life in terms of graphene growth cycles. The copper foil is designed to be discarded after a certain number of uses, eliminating the need for costly monocrystal substrates while maintaining acceptable graphene quality through controlled oxygen content and grain structure
Solution Approach 2:
The patent changes the key parameter of oxygen content in the copper substrate from trace levels (as in monocrystals) to a controlled range of 50-200 ppm. This parameter change, combined with controlling crystal grain size, allows ordinary copper foil to achieve catalytic performance suitable for graphene growth, resolving the contradiction between substrate quality and cost
2Manufacturing precision
If a monocrystal metal substrate is used for graphene production, then the quality and uniformity of graphene are improved, but the area of the substrate is limited
Solution Approach 1:
The patent enables the use of large-area ordinary copper foils by controlling their microstructure (oxygen content and grain size) to provide sufficient catalytic activity across the entire surface. This allows production of large-area graphene without being constrained by the size of expensive monocrystal substrates
Solution Approach 2:
By controlling the oxygen content (50-200 ppm) and crystal grain size (10-100 μm) parameters, the patent transforms ordinary copper foil into an effective graphene catalyst that maintains uniformity across large areas, breaking the area limitation of monocrystal substrates
3Ease of manufacture
If copper foil with high oxygen concentration is used, then the cost is reduced, but the sheet resistance increases and graphene quality deteriorates
Solution Approach 1:
The patent identifies oxygen content as a critical parameter that can be optimized to a specific range (50-200 ppm). This parameter change allows the copper foil to maintain both low cost (using ordinary rather than high-purity copper) and high graphene quality (through sufficient catalytic activity), resolving the contradiction between cost and quality
4Manufacturing precision
If the copper foil surface is made smooth, then the graphene quality is improved, but the crystal grain size control becomes more difficult
Solution Approach 1:
The patent changes the approach from controlling surface smoothness as a separate geometric parameter to controlling it through the crystal grain size parameter (10-100 μm). By controlling the grain structure during copper foil manufacturing, both surface smoothness and crystal grain size are simultaneously optimized, reducing overall processing complexity
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 enables the production of high-quality, large area graphene at lower costs with improved sheet resistance, making it suitable for practical applications.
Implementation Method 1
the copper acts as the catalyst, carbon atoms produced by thermal decomposition of a hydrocarbon gas form graphene on the surface of the copper
Implementation Method 2
a sheet-like monocrystal graphitized metal catalyst is contacted with a carboneous substance and then is heat treated to grow the graphene sheet (Chemical Vapor Deposition (CVD) method)
Implementation Method 3
carbon atoms produced by thermal decomposition of a hydrocarbon gas form graphene on the surface of the copper
Data Source
Figure 1(a)~1(c)
AI summary
A copper foil for producing graphene including Cu having a purity of 99.95% by mass or more.