The study of the dependence of dielectric properties, electric modulus, and ac conductivity on the frequency and voltage in the Au/(CdTe:PVA)/n-Si (MPS) structures

The dielectric properties, electric modulus, loss tangent (tan delta), and ac conductivity of the fabricated Au/(CdTe:PVA)/n-Si (MPS) structures were investigated in wide-range frequency. By using the capacitance/conductance-voltage-frequency (C/G-V-f) measurements, the real/imaginary components of complex dielectric constant (epsilon', epsilon '')/electrical modulus (M', M ''), loss tangent (tand), and sigma(ac) were calculated in wide-range frequency (2 kHz-0.7 MHZ) and voltage (+/- 2.5 V), and all results show that these parameters are a strong function of voltage and frequency. The observed decreases of epsilon' and epsilon '' with increasing frequency were attributed to the existence of N-ss, interlayer, and dipole polarizations. The value of epsilon' was calculated as 128.38 (at 2 kHz and 2.5 V), which is quite higher than the maximum value of traditional SiO2. ln(sigma(ac))-ln(f) plot for 0.7 V shows three linear parts, indicating three different conduction mechanisms at low, intermediate, and high frequencies. These results show that the fabricated MPS structures can be successfully used instead of traditional metal-insulator-semiconductor as ultra-capacitors, which can use more electronic charges or energy.