Interdiffusion at the Molybdenum–TEOS Interface in Flat and Nanostructured Systems during Graphene CVD

High Resolution Image Download MS PowerPoint Slide The integration of graphene with metallic layers provides a versatile platform for hybrid materials in electronic and optical technologies. Here, we investigate interdiffusion phenomena at the molybdenum–tetraethyl orthosilicate (TEOS)–derived SiO 2 interface during graphene growth by chemical vapor deposition (CVD). Graphene was grown on a 35 nm thick continuous sputtered molybdenum film and on nanostructured molybdenum patterns defined by electron beam lithography, both supported on a 1.6 μm thick TEOS–derived SiO 2 layer. The samples were characterized by Rutherford backscattering spectrometry, secondary ion mass spectrometry, X-ray diffraction, and scanning and transmission electron microscopy. On the flat molybdenum film, the CVD process leads to the formation of Mo–Si and Mo–C phases and to the growth of approximately 15 graphene layers. In contrast, nanostructured molybdenum undergoes solid-state dewetting, resulting in morphological instability and the formation of only about 5 graphene layers. These results demonstrate that catalyst geometry critically influences graphene thickness: interdiffusion is predominantly unidirectional in planar films, whereas it becomes multidirectional in confined nanostructures, leading to partial carbon loss and enhanced silicon incorporation. The loss of structural homogeneity below a critical lateral dimension highlights the key role of interfacial diffusion and surface morphology in controlling graphene growth on metal–oxide substrates.