Au/n-Si(MS) structures with a high dielectric interlayer(0.03 graphene-doped PVA) are fabricated to investigate the illumination and voltage effects on electrical and dielectric properties by using capacitance-voltage(C-V) and conductance-voltage(G/ω-V) measurements at room temperature and at 1 MHz.Some of the main electrical parameters such as concentration of doping atoms(N_D),barrier height(Φ_b(C — V)),depletion layer width(W_D)and series resistance(R_s) show fairly large illumination dispersion.The voltage-dependent proGle of surface states(N_(ss)) and resistance of the structure(R_i) are also obtained by using the dark-illumination capacitance(C_(dark)-C_(ill)) and Nicollian-Brews methods,respectively.For a clear observation of changes in eJectricaJ parameters with illumination,the values of No,W_D,Φ_b(C — V) and R_s are drawn as a function of illumination intensity.The values of N_D and W_D change almost linearly with illumination intensity.On the other hand,R_s decreases almost exponentially with increasing illumination intensity whereas Φ_b(C — V) increases.The experimental results suggest that the use of a high dielectric interlayer(0.03 graphene-doped PVA) considerably passivates or reduces the magnitude of the surface states.The large change or dispersion in main electrical parameters can be attributed to generation of electron-hole pairs in the junction under illumination and to a good light absorption.All of these experimental results confirm that the fabricated Au/0.03 graphene-doped PVA/n-Si structure can be used as a photodiode or a capacitor in optoelectronic applications. Au / n-Si (MS) structures with a high dielectric interlayer (0.03 graphene-doped PVA) are fabricated to investigate the illumination and voltage effects on electrical and dielectric properties by using capacitance-voltage (CV) and conductance-voltage (G / ω-V) measurements at room temperature and at 1 MHz. Home of the main electrical parameters such as concentration of doping atoms (N_D), barrier height (Φ_b (C - V)), depletion layer width R_s) show fairly large illumination dispersion.The voltage-dependent proGle of surface states (N_ (ss)) and resistance of the structure (R_i) are also obtained by using the dark-illumination capacitance (C_ (dark) -C_ (ill) ) and Nicollian-Brews methods, respectively. For a clear observation of changes in eJectricaJ parameters with illumination, the values ​​of No, W_D, Φ_b (C - V) and R_s are drawn as a function of illumination intensity. The values ​​of N_D and W_D change almost linearly with illumination intensity. Off the other hand, R_s decreases almost exponentially with increasing illumination intensityμβ (C - V) increases. The experimental results suggest that the use of a high dielectric interlayer (0.03 graphene-doped PVA) considerably passivates or reduces the magnitude of the surface states. in the main electrical parameters can be attributed to generation of electron-hole pairs in the junction under illumination and to a good light absorption. All of these experimental results confirm that the fabricated Au / 0.03 graphene-doped PVA / n-Si structure can be used as a photodiode or a capacitor in optoelectronic applications.