Dielectric Properties of Au/PVA (Cobalt-Doped)/n-Si Photoconductive Diodes

The voltage (V) and frequency (f) dependence of dielectric parameters such as the dielectric constant (ε′), dielectric loss (ε″), dielectric loss tangent (tan δ), real and imaginary parts of electrical modulus (M′ and M″), and alternating-current (AC) electrical conductivity (σ _AC) of Au/PVA (cobalt-doped)/n-Si structures have been investigated by using experimental admittance measurements conducted at room temperature. The values of ε′, ε″, and tan δ were found to be strong functions of voltage and frequency, especially at low frequencies in the positive voltage region. It was observed that the values of ε′ and ε″ increase as the frequency decreases. The M′ values increase with increasing frequency due to increasing dielectric relaxation, while M″ values, in general, remain stable as frequency is changed. The σ _AC values at each bias voltage increase with increasing frequency.