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.