Fig. 1: The crack-free transfer of large-area graphene films onto SiO2/Si wafers and polyethylene terephthalate (PET) substrates.
a Illustration of techniques for transferring graphene onto destination substrates free of cracks and contamination. Before the bubbling-based separation, the lamination of the rigid thermal release tape (TRT) onto the supporting films is essential for large-scale operability. b Mechanism illustration of the heat-induced deformation and resulted conformal contact. Heat treatment would enable the evaporation of oxhydryl groups-containing volatile molecules (OVMs) and the height change (from h1 to h2) of the supporting films. c Photograph of 4-inch graphene single-crystal transferred onto SiO2/Si wafers. The region below the black dash line is not covered by graphene, because this region was not coated by supporting films for being connected with electrodes during bubbling delamination. d, e Statistics of Macro-intactness (orange) and Micro-intactness (blue) of as-transferred graphene on 4-inch SiO2/Si (d) and A4-sized PET (e). d Optical microscopy (OM) image of graphene on SiO2/Si substrates at 5× magnification. e A4-sized scanned image of graphene on PET. Note that graphene in c, d was transferred by cedrol (10 wt%)/PMMA.
