© 2020 Elsevier B.V.Al/p-Si (MS) type SBDs with/without (PVP–TeO2: Cd) interfacial layer was fabricated in the same conditions to investigate Cd impurities on its electrophysical parameters using I–V and Z-f measurements. Structural and optical properties of the (TeO2: Cd) nanostructures were characterized using XRD, FE-SEM, EDX, and UV–Vis techniques. The existence of Cd impurities and formation of TeO2 nanostructures was confirmed by EDX and XRD techniques, respectively. The values of barrier height (ΦB0), ideality factor (n), series resistance (Rs) were derived from the IF-VF data as 0.65 eV, 5.60, 4.80 kΩ for MS and 0.54 eV, 4.83, 0.27 kΩ for MPS SBD, respectively. The energy-dependent profile of surface states (Nss) was also extracted from IF-VF data by assuming voltage-dependent of BH and n. The existence of impurities in the interlayer leads to a decrease of n, Rs, ΦB0, but an increase of leakage current, rectifying ratio (IF/IR), and conductivity.