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 (Ea) 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 (Vbi), barrier height (φb), and Fermi energy (EF) increase with increasing temperature. Moreover, donor concentration (ND) and image force barrier lowering (∆φb) decrease with temperature increment. In addition, series resistance (Rs) 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.