Polymer-free transfer of large area CVD-grown graphene film for THz application

High-quality graphene films were synthesized on copper (Cu) via Low-Pressure Chemical Vapor Deposition (LPCVD) (950–1000 °C). Addressing critical challenges in graphene integration, we report a novel, polymer-free dry transfer technique for large-area graphene from Cu foil to diverse insulating substrates (Si/SiO2, pure silicon, quartz, PET). This method effectively circumvents polymer residue and structural damage common in wet transfer, preserving graphene's intrinsic properties crucial for high-performance applications. The transferred graphene's robust and pristine nature is particularly promising for Terahertz (THz) communication applications, leveraging its unique electronic and optical properties at THz frequencies. Monolayer growth and film quality were rigorously confirmed by Raman spectroscopy (layer number, defect density), Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM) (surface topography, homogeneity, structural integrity). Electrical characterization via Van der Pauw and Transfer Length Method (TLM) confirmed high film quality, exhibiting a sheet resistance of 1.27 kΩ/sq and a low contact resistance of 3.6 Ω⋅mm for a contact width of 100 μm. This scalable, polymer-free transfer method offers a significant pathway for realizing high-performance graphene-based technologies, especially in rapidly developing THz communications.