The photo-electrical properties of the p-Si/Fe(II)–polymeric complex/Au diode

• Fe(II)–polymeric complex with Fe(II) of Schiff base polymer was synthesized.
• The Fe(II)–polymeric complex exhibited semiconductor property.
• The p-Si/Fe(II)–polymeric complex/Au diode was prepared.
• The photo-electrical properties of the diode were investigated.

In this study, the Schiff base monomer was prepared by a common condensation method of salicylaldehyde and (E)-3-amino-4-((3-bromophenyl)diazenyl)-1H-pyrazol-5-ol. The poly(Schiff base) was synthesized from the oxidative polycondensation of the Schiff base monomer with NaOCl in an aqueous alkaline medium. After obtaining Schiff base polymer, Fe(II)–polymeric complex with Fe(II) of Schiff base polymer was successfully synthesized. Ligand, monomer, Schiff base polymer and Fe(II)–polymeric complex were characterized using elemental analysis, 1H NMR, 13C NMR, FT IR, GPC, UV–vis and magnetic susceptibility. Then, we fabricated the p-Si/Fe(II)–polymeric complex/Au diode and investigated the electronic and photoconductivity properties of the p-Si/Fe(II)–polymeric complex/Au diode by current–voltage measurements under dark and various illumination conditions. We calculated the electrical and photo-electrical parameters of the p-Si/Fe(II)–polymeric complex/Au diode such as the rectification ratio (r), ideality factor (n), barrier height (Φb), Richardson constant (A*), series (Rs) and shunt resistance (Rsh) and photocurrent (Iph), responsivity (R) and photoconductivity sensitivity (S). The obtained n values confirm the presence of a combination of recombination and diffusion currents in the p-Si/Fe(II)–polymeric complex/Au diode. The r, n, Φb, Rs and Rsh values of the p-Si/Fe(II)–polymeric complex/Au diode decreased with increasing illumination intensity. The Iph, R and S values of the p-Si/Fe(II)–polymeric complex/Au diode increased with increasing illumination intensity. The synthesized Fe(II)–polymeric complex exhibits semiconductor property, it can be used in production of the metal-semiconductor (Schottky) diode and it is sensitive to light. The p-Si/Fe(II)–polymeric complex/Au diode exhibits a photoconductivity effect.

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