Dielectric properties and electric modulus of Au/PPy/n-Si (MPS) type Schottky barrier diodes (SBDS) as a function of frequency and applied bias voltage

Abstract

Au/PPy/n-Si Schottky barrier diodes (SBDs) were fabricated by forming polypyrrole (PPy) organic layer on n-Si using the spin coating technique. Frequency-dependent dielectric constant (ε′), dielectric loss (ε″), loss tangent ( tan δ), real and imaginary parts of electrical modulus (M′ and M″) and AC electrical conductivity (σ ac ) parameters of the structure were investigated in the frequency range of 10–500 kHz. It was found that the values of the ε′, ε″ and tan δ, in general, decrease with increasing frequency while an increase is observed in σ ac , M′ and M″. The tan δ and M″ also exhibit a peak at about zero-bias voltage, while peak intensity weakens with increasing frequency. The values of ε′ and M′ decrease with increasing voltage while an increase is observed in ε″, tan δ, σ ac and M″. These changes in ε′, ε″, tan δ, M′, M″ and σ ac values was attributed to surface charge polarization and the particular density distribution of surface states localized at PPy/n-Si interface.