Cerium Ammonium Nitrate Oxidation for Graphene Patterning
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Solution Overview
Problem
The high cost and inefficiency of oxygen plasma etching for patterning graphene and carbon nanotubes in electronic devices, which results in poorly defined edges and increased manufacturing costs, hinder the development of low-cost, medium-performance electronic devices.
Innovation Solution
The use of Ce(IV) salts, such as cerium ammonium nitrate, for chemical oxidation of carbon nanotubes and graphene, which are dissolved in water and applied to substrates to create patterns of non-conductive areas, effectively oxidizing the materials and reducing conductivity, thereby allowing for cost-effective patterning without plasma treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If oxygen plasma etching is used for patterning graphene and carbon nanotubes, then the patterning process can be performed, but the manufacturing cost increases and the edge definition becomes poor
Solution Approach 1:
The patent replaces the mechanical/physical plasma etching system with a chemical oxidation system using cerium ammonium nitrate solution. This chemical approach eliminates the need for expensive vacuum equipment and plasma generators, thereby reducing manufacturing cost while achieving well-defined edges through controlled chemical reaction at the pattern boundaries
Solution Approach 2:
The patent changes the etching mechanism from physical plasma bombardment to chemical oxidation by introducing cerium ammonium nitrate solution. By controlling parameters such as solution concentration, treatment time, and temperature, the process achieves precise edge definition without the high costs associated with plasma equipment and operation
2Productivity
If oxygen plasma etching is used for patterning, then the carbon materials can be etched, but the process becomes time consuming and requires vacuum conditions
Solution Approach 1:
The patent substitutes the complex plasma generation and vacuum maintenance system with a simple liquid-phase chemical oxidation process. The cerium ammonium nitrate solution can be applied directly to the carbon material at atmospheric pressure, eliminating the need for vacuum chambers and plasma power supplies, thereby simplifying the overall process while maintaining etching efficiency
Solution Approach 2:
The patent employs a liquid-based chemical oxidation system where cerium ammonium nitrate solution is applied to the carbon material surface. This hydraulic approach replaces the gaseous plasma system, allowing the process to occur at atmospheric pressure without complex vacuum equipment, thus reducing device complexity while preserving productivity
3Reliability
If photolithography is used to protect device areas before plasma etching, then the device area can be protected, but the overall manufacturing cost increases
Solution Approach 1:
The patent extracts and eliminates the photolithography step from the patterning process by using direct chemical oxidation with cerium ammonium nitrate solution. The solution can be selectively applied to areas requiring etching without needing photoresist masks, thereby maintaining reliable device area protection while significantly reducing manufacturing cost by removing an entire process step
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 method significantly reduces the cost of manufacturing by eliminating the need for plasma etching, providing well-defined non-conductive patterns and enabling the production of low-cost, medium-performance electronic devices with improved edge definition and reduced functional group contamination.
Implementation Method 1
the Ce (IV) salt is selected from a Ce (IV) ammonium salt of a nitrogen oxide acid and is dissolved in a solvent comprising water. The process is conducted for a period of time and at a temperature and solution concentration sufficient to substantially oxidize the carbon material to produce an oxidized material that is substantially non-conducting
Data Source
AI summary
A process comprises combining a Ce (IV) salt with a carbon material comprising CNT or graphene wherein the Ce (IV) salt is selected from a Ce (IV) ammonium salt of a nitrogen oxide acid and is dissolved in a solvent comprising water. The process is conducted under conditions to substantially oxidize the carbon material to produce an oxidized material that is substantially non-conducting. After the oxidation, the Ce (IV) is substantially removed from the oxidized material. This produces a product made by the process. An article of manufacture comprises the product on a substrate. The oxidized material can be formed as a pattern on the substrate. In another embodiment the substrate comprises an electronic device with the oxidized material patterning non-conductive areas separate from conductive areas of the non-oxidized carbon material, where the conductive areas are operatively associated with the device.