Holey carbon film copper grids may serve the purpose. Though these grids are costly but are good for doing EFTEM/EELS for carbon containing materials. Please see the website for better information. http://www.agarscientific.com/holey-carbon-films.html (However, you still can use ordinary 300 mesh copper grids.)

We've used those holey carbon film copper grids and you may find the corresponding HRTEM micrographs in our paper, Phys.Chem.Chem.Phys., 2016, 18, 26900-26912. (DOI: 10.1039/C6CP05154E)

You will likely look far away from the grid bars, so the material and mesh size is less important. Far more important is to make sure the grids are clean before adding your sample. Several hours of vacuum baking usually works well.

You may also consider the use of Si or SiNx grids. This with combined cleaning should make looking at carbon easy.

Article In situ investigation on the formation and metastability of ...

For your particle size, holey carbon film grid probably will be a good choice, lacey Formvar/Carbon grid will also be a good alternative because it is cheaper. Usually you can find your particles on the edges. 

Also this link might be helpful: https://www.tedpella.com/Support_Films_html/Support_Films_and_Substrates_Overview.htm#lacey-support-films

Following

Apart from the normal copper grids, you can use the holey carbon film copper grids for this purpose.