Abstract

Cadmium sulfide (CdS) is a promising n-type semiconductor, has been extensively studied for its optoelectronic applications. This work explores the impact of a CdS interlayer on the performance of silicon-based metal-semiconductor-metal Schottky diodes. CdS thin films were deposited on silicon (Si) and glass substrates via RF magnetron sputtering, with particular emphasis on the influence of sputtering pressure on their structural and optoelectronic properties. Field-emission scanning electron microscopy was employed to analyze the particle size distribution of the CdS films. Optical characterization revealed a marginal decrease in the optical bandgap from 2.38 eV to 2.36 eV. The Wemple-DiDomenico model was applied to derive dispersion energy parameters, yielding oscillator energies (Eo) between 4.08 eV and 4.32 eV and dispersion energies (Ed) ranging from 11.23 eV to 15.39 eV. The electrical characteristics of Ag/Si/Ag and Ag/CdS/Si/Ag Schottky diodes were systematically investigated through current density-voltage (J-V) measurements. Under illumination, key diode parameters were extracted using the thermionic emission model, Norde model, and Cheung model. The introduction of the CdS interlayer was found to significantly improve the Schottky barrier height, ideality factor, and overall diode performance. Critical parameters including leakage current, series and shunt resistance, and charge transport mechanisms were notably enhanced by the CdS layer, underscoring its pivotal role in optimizing Schottky diode characteristics.