Fig. 1: UV tape-assisted transfer of monolayer graphene and its characterizations.
From: Ready-to-transfer two-dimensional materials using tunable adhesive force tapes
a, Transfer process of monolayer graphene from Cu(111)/sapphire to a SiO2/Si substrate using the UV tape. b, Optical micrograph of a transferred graphene sheet. The upper half was exposed to the UV light, while the lower half was kept dark. These images indicate that the UV light is essential for the uniform transfer of graphene. c,d, Optical images of the as-grown Cu surface with aligned graphene grains (c) and the graphene grains after transfer onto SiO2 (d). e, Transfer yield of a monolayer graphene sheet calculated for 10 transfer batches. Inset is a photograph showing the removal of the UV tape, leaving graphene on the surface of a SiO2/Si substrate (10 × 20 mm2). f,g, Raman spectra (f) and mapping of the ID/IG intensity ratio (g) of a transferred graphene sheet. The numbers in f indicate the measured positions in g. h, Histograms of the electron mobilities of the graphene FETs. The monolayer graphene was transferred with the UV tape (upper) and PMMA (lower). The measurement was conducted at room temperature. i, Photograph of graphene stack made by transferring three sheets of large monolayer graphene, where L1, L2 and L3 correspond to the first, second and third transferred graphene layers, respectively. a.u., arbitrary units.
