Wednesday, March 12, 2008

Overview of Graphene Synthesis

Here's a step-by-step guide to the current synthetic strategies for making graphene:

1. Exfoliated Graphene: Great step-by-step demo from Scientific American
A. Take a piece of scotch tape and some highly ordered graphite.
B. Put the piece of scotch tape on the graphite, then rip it off.
C. Repeat a lot of times.
D. Deposit on a SiO2 substrate.
E. Look for graphene layers.

Pros: Cheap and easy enough you can pay an undergrad to do it. No special equipment needed, and you can find the thickness of the graphene layers based on the color of the SiO2.
Cons: Gives very uneven films, meaning it is very time-consuming to find where the graphene (as opposed to graphite) is. Also labor intensive, which is great for students but bad for industry.

2. Epitaxial Graphene
A. Take a SiC wafer.
B. Heat it to 1100 C.

Pros: Produces the most even films of any method, doesn't require a lot of really complicated steps.
Cons: Gives few-layer graphene (FLG), usually 5-10 layers at best. Also, not everyone has such a fancy (or hot) oven, and the technique isn't very versatile since you can't really functionalize something you grow from thermal decomposition.

3. The Graphene Oxide Approach
A. Oxidize highly-ordered graphite with HNO3 and H2SO4.
B. Sonicate it, then purify via centrifuging.
C1. Reduce to graphene-ish material, then put on substrate, or:
C2. Put on substrate, then reduce to graphene-ish material.

Pros: More versatile than epitaxial methods, less time-consuming and easier to scale up than exfoliation methods.
Cons: Difficult to keep solution from re-aggregating into graphite; after reduction, graphene layers are still partially oxidized, potentially changing electronic, optical, and mechanical properties.

4. CVD Graphene
A. Pump in hydrocarbon gas (usually CH4), sometimes under vacuum
B. Watch as the carbon arranges into graphene on your surface (often a metal surface like nickel)

Pros: Great for making large amounts of film, requires very little labor
Cons: Often makes unpredictably arranged multilayers, with defects being linked to the substrate you're using. Also, the metal surfaces on which this works best are not what you want to build graphene devices on top of.

Well, there you have it. Enjoy.

(Updated Feb. 20, 2009 to include CVD)

19 comments:

Anonymous said...

what is about graphene/Ni(111)?

Anonymous said...

Hi! Many thanks for the great blog. I have a question concerning the first method (scotch method) for graphene synthesis:
- What is meant by rinse the tape? Do you take the tape+cleaved graphite and put it in a special solution? What kind of solution would that be? Thanks for taking the time to give some more details on this. Of course any intresting paper on the topic is welcome! Thanks :-)

Rob W said...

Anonymous #1: Post updated

Anonymous #2: I've posted a very nice step-by-step demo, with pictures, from Scientific American. I must have been confused, because they don't rinse the tape.

vishalkumar said...

Dear Sir,
Thanks for giving such a nice information. Is there any technique for mass production of single layer graphene?

Rob W said...

The short answer is, no, there's not a technique for mass production of single layer graphene at this time.

Rahul said...

what does scotch tape refer to?
and what will it cost to create a graphene layer

Arturo Mora Lazarini said...

Congratulations, your blog is interesting, recently I began a Doctorade in NN (nanoscience & nanotech) researching about synthesis & characterization of one layer graphene, its dificult I know, but not impossible.

I'll keep reading your notes and papers.

Anonymous said...

what about the Raman spectrum of graphene? 2D band should be there or it is not neccessary?

tessy said...

How is the electrical conductivity of few layer(3-5 layer) graphene?

Mutie said...

What happens if you attempt the CVD method on Si?

Dennis said...

Graphene Synthesis by Ion Implantation

http://apl.aip.org/resource/1/applab/v97/i18/p183103_s1

Ma. Monica said...

"Also labor intensive, which is great for students but bad for industry."


LOL!

Sujith Jose said...

A very good overview of adva and disadva. tnx a lot

Nanoali said...

Thats good lesson.Can you justify what will people do with this nanogram product.Please share something which can be feasible at little large scale.So that company can see it from commercial point of view or researcher can use for their experiments.I have CVD method to produce all variants of graphene,if you need that one contact me at mnsmart@yahoo.com

Nanoali said...
This comment has been removed by a blog administrator.
Izzy Naluri said...
This comment has been removed by the author.
Izzy Naluri said...

A lot of questions here are trying to get short cut answers to actual research question/problems!! Its hard for the author to produce one for one answers to your questions because you need to do a lot of literature review to find the answers. I think its best for the author to suggest a good review paper on graphene as a starting point on reading the latest advances in graphene.

Manikanta anupoju said...

plz help me in knowing the chemistry, reasons behind the synthesis of Graphene by Hummers method.

Manikanta anupoju said...

can we distinguish the Scanning Electron Microscope images of Graphene oxide and Graphene? What are the differences in their structures? why?