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

Abstract

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 (Gω) 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/ω values increased with a decreasing frequency, while increasing in depletion and accumulation regions with increasing voltages. However, particularly, the Rs - 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- 6.58×10 12 cm-2.eV-1 with a relaxation time constant of 157- 31.5 μ 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 (max) is 111 which is very higher than the maximum value of the conventional materials (SiO2 (3.8), SnO2 (7.5), and so on) and appropriate doped materials to PVP. The results indicate that the graphene-PVP thin film with the high max value has a potential in metal-organic-semiconductors device technologies instead of a conventional device.