This paper explores the effects of the organic interfacial layer on the electrophysical characteristics of Schottky barrier diodes (SBDs). Three types of SBDs were fabricated: Au-Si (referred to as MS), Au/PVC/Si (referred to as MPS1), and Au-/PVC:Fe/Si (referred to as MPS2). Fe nanopowders were subjected to analysis using XRD, SEM, and EDX techniques to investigate their structural and optical characteristics. To investigate the conduction mechanisms of these diodes, I-V characteristics were examined using thermionic-emission (TE), Cheung, and Norde functions. The surface-state density (N ss ) distribution of energy was determined by analyzing the current–voltage (IF-VF) curve under forward bias conditions. This analysis considered the voltage-dependent barrier height (BH) and ideality factor (n(V)). The results demonstrated that the polymeric interlayer without Fe nanoparticles reduced N ss by a factor of 7, while the presence of Fe nanoparticles led to a two-order magnitude decrease, resulting in improved efficiency in comparison with MS structures. The obtained results indicated that including a polymeric layer in MPS structure enhanced their electrophysical features compared to MS diodes, and significantly increased rectification by 15–45 times. In summary, the existence of an organic interfacial layer significantly altered the conduction mechanisms and electrophysical characteristics of MPS diodes. It was found that the addition of Fe nanoparticles in the interlayer resulted in substantial improvements in N ss , efficiency, rectification, and conduction characteristics compared to MS diodes.