Comprehensive Raman spectroscopic characterization of CVD-grown graphene: correlating growth parameters, transfer-induced effects, and substrate interactions for device-grade applications

Abstract

Abstract Chemical vapor deposition (CVD) is a scalable route for synthesizing large-area graphene; however, achieving uniform and device-grade films remains challenging due to strong sensitivity to growth parameters. In this work, graphene was synthesized on copper foils using methane flow rates between 15 and 45 sccm and subjected to controlled slow- and fast-cooling regimes. Transferred films were characterized on glass, SiO 2 /Si, and amorphous Ge substrates using Raman spectroscopy, and supported by optical microscopy and scanning electron microscopy (SEM). Fast-cooled samples exhibit sharp G and 2D bands with suppressed D-band intensity, indicating low defect density and improved crystallinity, whereas slow-cooled samples show weak Raman signatures and poor spatial uniformity. SEM analysis confirms sparse and discontinuous graphene growth under slow cooling, and dense and continuous graphene domains under fast cooling. Benchmarking against commercial CVD graphene reveals comparable Raman signatures and morphological continuity. These results demonstrate that cooling rate critically governs surface carbon retention and graphene quality, while combined Raman and microscopy analyses provide a robust framework for CVD graphene optimization.