Frequency and temperature dependence of dielectric properties and capacitance–voltage in GO/TiO₂/n-Si MOS device

Abstract

Dielectric properties and capacitance–voltage of GO/TiO₂/n-Si junction were investigated in frequency range 10–2 × 10⁷ Hz and temperature (233–363 K). Reliance of $\varepsilon^{\prime}$, $\varepsilon^{\prime\prime}$, tanδ, Mʹ, Mʺ, impedance, and ac conductivity on frequency and temperature were studied. From results, it is found that $\varepsilon^{\prime}$ increases with increasing frequency at low-frequency region, while that it decreases at high frequencies. $\varepsilon^{\prime\prime}$ decreases with frequency (f) increment in the range 10–56 Hz and 1619–12195 Hz. It is observed the decrement of tanδ with increasing frequency in higher range 1,355,210–2 × 10⁷ Hz. Real part of electric modulus (Mʹ) reduces with increment frequency. Conductivity rises with rising temperature. Moreover, activation energy (E_a) values decrease with increasing f then increase at higher f. Different parameters, such as carrier density, built-in potential, and barrier height, were derived from the reverse bias C⁻²–V curves. It is found that, built-in-voltage (V_bi), barrier height (φ_b), and Fermi energy (E_F) increase with increasing temperature. Moreover, donor concentration (N_D) and image force barrier lowering (∆φ_b) decrease with temperature increment. In addition, series resistance (R_s) decreases with temperature and frequency increment. In addition, this MOS structure GO/TiO₂/n-Si works as a device, and by controlling the temperature, frequency, and voltage, the required properties from this device can be adjusted to make it suitable for any required applications; this is obvious from investigated dielectric properties.