Surface states and series resistance effects in Au/(HgS-PVA)/n-Si capacitors

Abstract HgS nanomaterials were synthesized using an ultrasound-assisted method, and their optical and morphological properties were analyzed through UV–Vis spectroscopy and scanning electron microscopy (SEM). The capacitance–voltage ( C – V ) and conductance–voltage ( G/ω–V ) measurements of the Au/(HgS-PVA)/n-Si (MPS) capacitor were conducted across a frequency range of 1 kHz–5 MHz. The experimental data were used to investigate the effects of surface states ( N ss ) and series resistance ( R s ) . Both C and G / ω increased at lower frequencies, as the surface states could follow the AC signal, contributing to the overall response. The density of N ss was derived using the high-low frequency (HF) capacitance method and parallel conductance technique, while Nicollian–Brews’ method was employed to extract the R s . This study reveals that the conductance method yields higher values than the HF C – V method, attributed to its sensitivity to fast interface states and distributed trap time constants. The observed frequency-dependent losses in G p / ω measurements confirm the presence of a continuous trap distribution near the HgS-PVA/n-Si surface, significantly influencing device reliability. The average N ss was calculated to be ~ 10 12 eV⁻ 1 cm⁻ 2 , indicating a well-controlled interface. The obtained N ss and R s values suggest that the HgS-PVA nanocomposite is a promising alternative to conventional insulating layers (e.g., SiO₂ or SnO₂) in electronic devices, thanks to its favorable electrical properties.