We differentiated the effects of Cu films deposited on single crystalline a-, r-, and c-plane sapphire substrates upon graphene films synthesized with atmospheric pressure chemical vapor deposition (CVD). The data illustrate that the realization of high-crystalline Cu film is dependent not only on the crystallinity of underlying substrate, but also on the symmetric match of crystallographic geometry between metal film and substrate. We also systematically investigated the effects of PMMA removal on the Raman I D/I G and I G/I 2D values of transferred graphene. The results reveal that different PMMA removal methods do not alter the I D/I G values; instead, the residue of PMMA increases the I G/I 2D values and the thermal decomposition of PMMA leads to higher I G/I 2D values than the removal of PMMA with acetone. The effects of PMMA removal on variations of the Raman spectra are also discussed.
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