Graphene is the new wonder material for large-area flexible electronics. Particularly hard and resilient, as it is a chemical relative of diamonds, coal or the graphite of pencil leads - only better, because it conducts electricity and heat extremely well and is extremely flexible. In addition, with only one atomic layer, it is one of the thinnest materials in the universe – less than a millionth of a millimeter thick. And therefore suitable for numerous possible applications.
Chemical vapor deposition (CVD) process
However, there is often still a lack of proven manufacturing processes for this application. However, there are already various methods for the large-scale synthesis of graphene. Chemical vapor deposition has proven to be promising. The starting material, carbonaceous gas (so-called precursors), is passed over a substrate and chemically decomposed, whereby graphene is deposited as a solid-state film, i.e. a new layer is formed.
The so-called precursors are usually thermally disassembled. By heating the substrate. However, this leads to the restriction that it must be a substrate that can withstand the heat load. However, there are now different variants of the CVD procedure to reduce these negative effects.
Common CVD methods
Here is a brief overview of the common CVD methods.
- APCVD: Atmospheric Pressure CVD. Here, the typical working temperature is 400–1300 °C
- LPCVD: Low Pressure CVD. Here, the typical working temperature is 500–1000 °C
- PECVD: Plasma Enhanced CVD. Here, the typical working temperature is 200–500 °C
- ALD: Atomic Layer deposition. A cyclic process that makes it easier to achieve an exact layer thickness due to the different cycles.
- HFCVD procedure. Here, the typical working temperature is 150–1100 °C
Chemical vapor deposition (CVD) is still the most effective way to produce graphene. Still, not 100 percent optimal. Therefore, various CVD methods continue to be developed to improve the process and enable reliable large-scale production.
