Here I attached the optical image of single layer graphene. I always use to get some fractals or structure (dark colour in picture) in my sample. If someone could tell me what is it and how can I avoid it that would be appreciated.
We analysised with raman it shows signature of graphene.
I synthesised graphene using CVD menthod (H2--2sccm, CH4--35 sccm) and transfered to SiO2/Si via wet chemical method ( etch using APS and PMMA as support layer). and finally PMMA is removed by acetone and heat treatment.
In this sample graphene crystals are almost connected forming continuous film except few places. Those unconnected places are the dark places ( background). you can get raman peaks there because there can be graphene. Since graphene crystals have well defined edges, gaps in film also loolike some some sort of fractals. You can observe the individual crystals if you synthesize graphene by minimzing the growth time or lower the precursor flow rate.
SiC as substrate usually gives better crystalline compare to garphene on copper since its kind of epitaxy.
We to use the same recipe for growth of graphene .
but annealing cu folis prior to growth gives better crystallanity.
Kranthi, what mean annealing Cu foil prior to growth. can you give me in detail.
Is it different from annealing under H2 during synthesis
Its the same we anneal the cu foil in H2 for 2hrs to improve the crystallinity of the cu foil,
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