Effect of patterned silicon nitride substrate on Raman scattering and stress of graphene

Abstract

Graphene is widely used for nano-devices due to its distinctive band structure and fascinating properties. The substrates could significantly affect the properties of graphene and related devices. In this work, we investigate the effect of surface morphology and roughness of patterned silicon nitride substrates on Raman scattering and stress of graphene. We find that the Raman scattering of graphene depend strongly on surface morphology and roughness of patterned substrates. It is concluded that the peak red-shifts in 2D and G bands was due to the strain induced by patterns with different surface morphology (holes and trenches) and roughness. Furthermore, the effects of morphology of patterned area are much greater than the role of surface roughness in the induced strain of graphene. Due to the larger surface area (about 1.65 times), the strain in the grooves is greater than in holes, in spite of greater surface roughness in holes. Our results also reveal that the effect of pattern depth should be taken into account to understand the Raman peak shift and the strain change of graphene. Our work is fundamentally important for understanding the graphene properties on dependence of surface morphology of substrates and enhancing the interfacial strength of graphene-based devices.