▎ 摘　　要

Mechanical dry transfer of large-area graphene is increasingly applied in fabrication of graphene-based electronic devices, and adhesion energy of graphene/substrate interface is a key factor affecting reliability and performance of these devices. Herein, the adhesion energy of a graphene/poly(ethylene terephthalate) (PET) interface is measured by widely adopted double cantilever beam (DCB) fracture tests. Results show that the apparent adhesion energy of sandwiched interface is highly rate-dependent. When separation rate increases from 20 to 150 mu m s(-1), apparent adhesion energy increases by an order of magnitude. By examining fractured interfaces after DCB tests with micro-Raman spectroscopy, the graphene is found to be fractured and transferred in fragments, with residual tensile strain up to 3% for high separation rates. The results are contrary to earlier reports, where higher separation rate in dry-transfer process would typically enhance the dry transfer of graphene, resulting in better integrity and performance. Based on Raman spectroscopy measurements, three distinct decohesion modes are identified for PET-/graphene-/adhesive-sandwiched interface, which consistently explain the rate-dependent apparent adhesion energy. The complicated decohesion modes also suggest that an optimal separation rate should be used to properly measure the adhesion energy and improve the dry-transfer technique of graphene with minimum damage and residual strain.