The electrical properties of the fabricated Al/Gr/Al2O3/p-Si structure have been analyzed using frequency-dependent capacitance/conductance–voltage (C/G–V) measurements. Graphene (Gr) nanosheets were grown on to copper (Cu) catalyst substrate, which has 99.99% purity, by Chemical Vapor Deposition (CVD) technique, and then the Graphene was transferred on Al2O3/p-Si by the standard transfer process. The Graphene structures have been characterized by Raman Spectroscopy and Transmission Electron Microscopy (TEM) analyses, and the results of both analyses confirmed the monolayer/bilayer Graphene nanostructure. The forward and reverse bias G–V and C–V measurements of this structure have been performed in 10 kHz–400 kHz and at 300 K. The frequency dispersion in C and G can be evaluated for interface state density ( $$D_{{{\text{it}}}}$$ ) and series resistance ( $$R_{{\text{s}}}$$ ) values. The values of $$D_{{{\text{it}}}}$$ and $$R_{{\text{s}}}$$ are dependent on frequency and increase with decreasing frequency. The $$R_{{\text{s}}} - V$$ graph shows a peak form at all frequencies in the depletion region and vanishes with increasing frequency. The obtained results suggest that the prepared structure can be used in electronic device applications.
