Optical response of Au/n-Si schottky photodiode with an interface of graphite-Er2O3-doped polyvinyl alcohol (PVA) nanocomposite

Abstract

In this study, the photoconductive properties of a Schottky photodiode with the structure Au/PVA:Graphite-Er₂O₃/n-Si are investigated both in the dark and under varying light intensities. A thin layer of the polyvinyl alcohol doped with Graphite-Er₂O₃ is placed at the metal-semiconductor interface to create an Schottky photodiode with a metal-nanocomposite-semiconductor structure. The fabrication and preparation techniques are thoroughly documented. X-ray diffraction (XRD) is used to analyze the Graphite and Er₂O₃ nanostructures. Several key photoconductive properties, such as leakage or reverse-saturation current (I₀), electric potential barrier height (Φ_B0), and ideality factor (n), series/shunt resistances (R_s/R_sh), surface/interface state density distribution (N_ss), photocurrent (I_ph), photosensitivity (S), optical responsivity (R), and specific detectivity (D*) have been determined. Increasing light intensity leads to higher I₀ and n values, and lower Φ_B0 and R_s values. When studying the illumination dependency of photocurrent, the I_ph–P plots at zero bias voltage exhibit a linear behavior within an acceptable range. The PVA:Graphite-Er₂O₃ nanocomposite enhances the photosensitivity of the metal-nanocomposite-semiconductor type photodiode, optical responsivity, and specific detectivity by 1120, 2.40 mA/W, and 3.13 × 10 ¹ ⁰ Jones, respectively. These results suggest that the Au/PVA:Graphite-Er₂O₃/n-Si structure exhibits a promising photoresponse and could potentially replace traditional metal-semiconductor photodiode in optoelectronic devices and photovoltaic systems.