Figure 4
From: Realization of Large-Area Wrinkle-Free Monolayer Graphene Films Transferred to Functional Substrates
(a), Raman spectra of bare- and “top-” graphenes observed after a detachment of the Ti/glass substrate mechanically attached to the multi-layer graphene films transferred to the Ti/glass substrate. An inset of (a) showed a schematic structure to prepare the actual monolayer graphene from the multi-layer graphene films. (b), Transmittance of the bare- and “top-” graphenes observed after a mechanical detachment of the Ti/glass substrate. (c), Dielectric constants and dissipation factors for capacitors with Ti adhesion layers of 0, 2 and 10 nm as a function of the applied frequency. (d), The leakage current densities for capacitors with Ti adhesion layers of 0, 2 and 10 nm as a function of the applied voltage. (e), BMNO/graphene/Ti (10 nm)/glass capacitors showing a stable leakage current density of approximately 3 × 10−7 A/cm2 for an applied voltage of ±20 V. (f), Leakage current densities vs. the applied voltage for capacitors using graphene films transferred to the 10 nm-thick Ti adhesion layer coated on PET before (close circle) and after (open circle) bending at 0.6 cm for 30 s. Here, leakage current densities measured after ten times bending using the same samples were also shown in (f) for long-term mechanical stability of the graphene/Ti/PET. Dielectric and leakage currents for the BMNO/graphene/Ti/glass or PET capacitors were compared to those of the BMNO/Pt/Ti/glass or PET capacitors. Thickness of the Pt top and bottom electrodes was approximately 150 nm, respectively.
