High Dielectric Performance of Heterojunction Structures Based on Spin-Coated Graphene-PVP Thin Film on Silicon With Gold Contacts for Organic Electronics

The letter reports that frequency response of heterojunction structure based on a spin-coated graphene-PVP thin film on silicon with gold Schottky contacts and the electronic properties obtained by using capacitance (C) and conductance (G/ $\omega $ ) versus voltage characteristics in the frequency range from 5 to 5 MHz. Furthermore, the electronic magnitudes were calculated. The accumulation capacitance observed at 3 V changes from 920 to 1094 pF. Here, empirically, the C and G/ $\omega $ values increased with a decreasing frequency, while increasing in depletion and accumulation regions with increasing voltages. However, particularly, the ${R}_{s}$ - ${V}$ - ${f}$ curves have peaks in low frequency values in the accumulation and depletion regions, these peaks decreased at high frequencies. Besides, an interface trap state density of 5.6– $6.58\times10$ ¹² cm ⁻² .eV ⁻¹ with a relaxation time constant of 157– $31.5 ~\mu \text{s}$ was deduced. Additionally, the frequency and dc bias voltage-dependent dielectric characteristics show a huge dispersion, at room temperature. Experimentally, the high dielectric constant ( $\varepsilon '_{max}$ ) is 111 which is very higher than the maximum value of the conventional materials (SiO ₂ (3.8), SnO ₂ (7.5), and so on) and appropriate doped materials to PVP. The results indicate that the graphene-PVP thin film with the high $\varepsilon '_{max}$ value has a potential in metal-organic-semiconductors device technologies instead of a conventional device.