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 (G/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\omega $ </tex-math></inline-formula> ) 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/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\omega $ </tex-math></inline-formula> values increased with a decreasing frequency, while increasing in depletion and accumulation regions with increasing voltages. However, particularly, the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{s}$ </tex-math></inline-formula> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}$ </tex-math></inline-formula> - <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${f}$ </tex-math></inline-formula> 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– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$6.58\times10$ </tex-math></inline-formula> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−2</sup> .eV <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−1</sup> with a relaxation time constant of 157– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$31.5 ~\mu \text{s}$ </tex-math></inline-formula> was deduced. Additionally, the frequency and dc bias voltage-dependent dielectric characteristics show a huge dispersion, at room temperature. Experimentally, the high dielectric constant ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon '_{max}$ </tex-math></inline-formula> ) is 111 which is very higher than the maximum value of the conventional materials (SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (3.8), SnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (7.5), and so on) and appropriate doped materials to PVP. The results indicate that the graphene-PVP thin film with the high <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon '_{max}$ </tex-math></inline-formula> value has a potential in metal-organic-semiconductors device technologies instead of a conventional device.