Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

I am trying to produce graphene with few layers(<10) on a TEM-Grid. Until now I've been trying this with the scotch-tape-method with slight modifications. Unfortunately it requires a lot of time und there are often TEM-Grids without any flakes of the required thinness.

Is there a more efficient way to place graphene flakes having a size above $$ 150 \mu m * 150 \mu m $$ on a TEM-Grids? Is there a better quality of graphite blocks on the market than the SPI-1 quality?

share|improve this question
    
Is the grid something you can change? I think there is no method of producing graphene other than this scotch tape business. –  Ron Maimon Jul 14 '12 at 3:32
    
I don't think that I can change the grid. I was hoping that someone could tell me ways improve the scotch tape method. –  Stein Jul 14 '12 at 10:13
    
My guess is that you have some van-der-Waal forces between the grid and the graphene, perhaps the grid is a metal, and this is preventing you from cleaving the planes using the tape. You can try pressing harder to get more stick on the tape, but I think you might be better off putting a doubly-sticky tape on the grid, and trying with two tapes. Maybe this will allow cleaving. I don't know why the tape method stopped working, but it's as good a guess as any. I hope this doesn't wreck the grid. –  Ron Maimon Jul 14 '12 at 16:52
    
Van-der-Waal forces are far to weak. I try to produce a reasonable flake by putting two stripes of scotch tape against each other and splitting the stripes again. In case that I've got a stripe with a good flake I glue it on a TEM-Grid using crystal bond. Then I can remove the tape, hoping that the bond holds the flake. The bond can be removed with acetone. The problem is, that it require a lot of work, before you see whether you've got a good flake. –  Stein Jul 14 '12 at 17:40
1  
Like Ron, I believe that the tape method is the ever-so-sciency, cutting-edge method employed by most researchers in the field. You might try search the arXiv for some practical hints embedded in papers, but I find the easiest place to pick of this kind of practical advice is at conferences that these people attend. Talk to grad-students and post-docs. –  dmckee Jul 14 '12 at 18:13

1 Answer 1

There are, in fact, a wide variety of techniques for producing graphene other than the scotch-tape method. A very good review of these techniques can be found in this recent review article:

http://onlinelibrary.wiley.com/doi/10.1002/adma.201202321/abstract

It is extremely difficult to obtain the dimensions you require using the scotch-tape method. In my former group, even the student who was the best (in our group obviously) at using the scotch-tape method could go as far as 20-30 $\mu m$ long flakes. I am not aware of the world record for graphene flake sizes using this method. Our group, very soon, switched to the CVD method to produce large area graphene; we were successfully able to produce graphene on TEM grids using this method.

Since I don't know what your resources are, you may want to go through the above review article to find the method that is most convenient for you. My personal favorite is the layer-by-layer removal of graphene described in section 6.1 of the paper. I consider this method to be the chemical analogue of the scotch-tape method; except here you can precisely control the number of graphene layers!

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.