Production and characterization of vertical graphene--PVP/n-Si Schottky barrier diode in a wide frequency range

In this study, the electrical and dielectric properties of the heterojunction structure based on spin coated graphene-PVP thin film on silicon with Gold (Au) Schottky contacts were investigated using voltage-dependent Cm and Gm /ω measurements in a wide frequency range (5kHz-5MHz).Fermi energy level (EF), Series resistance (Rs), the density of allowed energy states in the conduction band (NC), interfacial state density (Nss), set-up voltage (Vbi), depletion layer width (Wd), maximum electrical field (Em), concentration of donor atoms (ND), potential barrier height (Фbo) were calculated. Experimentally, the capacitance and conductivity values increased with decreasing frequency, in the depletion and accumulation regions. In particular, the series resistance curve peaks at low frequency values in the accumulation and depletion regions, and this peak decreased towards high frequencies. The Nss –V values increased with towards positive bias regions, in the range of -3V to 3V. When the dielectric properties are examined, dielectric constant (ε'), ac conductivity (σac), dielectric loss (ε''), tangent loss (tanδ), real and imaginary parts (M' and M'') of electrical modules were calculated. According to the calculations, the dielectric constant and loss decreased with incresing frequency, and a very small change in the tanδ value was observed. AC conductivity, M' and M'' increased with increasing frequency. Experimentally, the high dielectric constant (εmax') is higher than the maximum value of conventional materials (SiO2 etc.) and doped materials suitable for PVP. The results show that the high value graphene-PVP thin film has potential in metal organic semiconductor device technologies rather than a conventional device. As a result, it was found that all these parameters were strongly frequency dependent for the Au/graphene-PVP/n-Si structure.