Graphene on Copper vs Graphene on Si/SiO₂: Which CVD Graphene Should You Buy?

When you buy CVD monolayer graphene, the first decision is the substrate: do you want graphene still on its copper growth foil, or graphene that has already been transferred onto a Si/SiO₂ wafer? Both are the same single layer of carbon atoms, but they suit very different workflows, budgets and skill sets. This guide compares graphene on copper vs graphene on SiO₂ so you can choose the right material for your project.

How CVD graphene is made

Large-area monolayer graphene is grown by chemical vapor deposition (CVD): a copper foil is heated to around 1000 °C in a mixture of methane and hydrogen, and the carbon forms a continuous single-atom layer on the copper surface. Copper is used because carbon has very low solubility in it, so growth naturally stops at one layer. The result is graphene on copper. Every other graphene substrate — silicon dioxide, glass, polymers — is made by transferring that film off the copper.

Graphene on copper foil

Monolayer graphene on copper foil is the material straight from the growth furnace. You transfer it yourself to whatever substrate you need.

Advantages

• Lowest cost per area — no transfer step has been paid for
• Total freedom of substrate: SiO₂/Si, quartz, sapphire, glass, PET, polyimide, TEM grids, nanopore membranes and more
• Control of your own transfer process, which matters if you are studying transfer, interfaces or contamination
• Available with a PMMA protective layer that protects the graphene during shipping and acts as the support film for wet transfer

Things to consider

• You need a transfer method — PMMA wet transfer or thermal release tape transfer — plus a copper etchant
• Transfer quality depends on technique; expect some practice before you get consistent coverage
• Store the foil in a dry place (a desiccator or nitrogen cabinet) to slow down oxidation of the copper under the graphene

Best for

Groups that work with many different substrates, flexible and transparent electronics, membranes and nanopores, transfer research, and anyone who needs large areas on a budget.

Graphene on Si/SiO₂ (90 nm)

Monolayer graphene on Si/SiO₂ has already been transferred onto a silicon wafer with a thermally grown oxide layer. It is ready for measurement or device fabrication the day it arrives.

Why 90 nm oxide?

A single layer of graphene is only about 0.34 nm thick, yet it becomes clearly visible in an optical microscope on silicon with roughly 90 nm or 285 nm of SiO₂, thanks to thin-film interference. That makes it easy to locate the graphene, align lithography masks and inspect for defects. When the silicon underneath is conductive (doped), it can also serve as a back gate for graphene field-effect transistors — ask us about the wafer doping if you need this.

Advantages

• Ready to use: no etching, no transfer, no learning curve
• Compatible with standard cleanroom processes — photolithography, e-beam lithography, metal evaporation, Raman mapping
• Back-gate option for transfer-curve (Dirac point) measurements on conductive silicon
• Available as 1 × 1 cm chips, 1-inch and 4-inch wafers

Things to consider

• Higher price per area than graphene on copper, because the transfer has been done for you
• The substrate is fixed: if you later need graphene on glass or polymer, you will need graphene on copper

Best for

GFET fabrication, biosensor prototyping, Raman and electrical characterisation, teaching labs, and any project where time matters more than material cost.

Graphene on copper vs Si/SiO₂: quick comparison

• Ready for devices: copper — after transfer; Si/SiO₂ — immediately
• Substrate choice: copper — any; Si/SiO₂ — silicon with 90 nm oxide
• Cost per area: copper — lower; Si/SiO₂ — higher
• Equipment needed: copper — etchant, transfer support (PMMA or thermal release tape), hot plate; Si/SiO₂ — none beyond your normal process
• Back gate: copper — depends on your substrate; Si/SiO₂ — possible with doped silicon
• Typical users: copper — materials and transfer researchers, flexible electronics; Si/SiO₂ — device engineers, sensor developers

What about the PMMA protective layer?

PMMA (poly(methyl methacrylate)) is a thin polymer coating applied over the graphene. On copper foil, it protects the graphene from scratches and contamination and becomes the support film during wet transfer: you etch the copper, scoop the PMMA/graphene film onto your substrate, let it dry and dissolve the PMMA in acetone. Choose graphene with PMMA if you plan a wet transfer and don’t have a spin coater; choose graphene without PMMA if you will use thermal release tape or your own polymer support.

Still not sure?

A common approach is to start with graphene on Si/SiO₂ to develop your device process quickly, then switch to graphene on copper with thermal release tape once you need other substrates or larger volumes. If you would rather skip fabrication entirely, our GFET chips are ready for sensing experiments. Contact us and we will help you pick the right option.