In this study, an Au/PAN/p-Si/Al Schottky photodiode incorporating a 1-(2-pyridylazo)-2-naphthol (PAN) organic interfacial layer was fabricated and systematically investigated. The structural, optical, and electronic properties of the PAN thin film were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Vis spectroscopy, and ultraviolet photoelectron spectroscopy (UPS). The PAN layer exhibited a semi-crystalline structure with nanoscale morphology, a wide optical band gap of approximately 3.7 eV, and high transparency in the visible region, making it suitable as an interfacial layer for optoelectronic applications. The electrical characteristics of the photodiode were evaluated based on current–voltage (I–V) measurements under dark and illumination conditions. The device exhibited clear rectifying behavior, confirming the formation of a Schottky junction. Key diode parameters, including ideality factor (n), barrier height (Φb), and series resistance (Rs), were extracted using thermionic emission and Norde methods. The results revealed that illumination significantly affected influences the junction properties, leading to an increase in saturation current and ideality factor, along with a reduction in barrier height. The optoelectronic performance of the device was further analyzed through photocurrent, responsivity (R), specific detectivity (D*), and normalized photo-to-dark current ratio (NPDR) measurements. The photocurrent followed a power-law dependence on illumination intensity with α values approaching unity under reverse bias, indicating efficient carrier generation and transport. The device demonstrated a high detectivity on the order of ~ 1011 Jones and a pronounced wavelength-dependent photoresponse, with superior performance under UV illumination. Transient measurements revealed stable and repeatable switching behavior with an ON/OFF ratio of ~ 50 and fast response times (τrise ≈ 0.2 s and τdecay ≈ 0.15 s). In addition, long-term stability tests confirmed that the device maintains its performance after prolonged operation. Overall, the incorporation of the PAN interfacial layer significantly enhances the photodetection performance by improving charge separation, suppressing recombination, and modulating the Schottky barrier. These findings demonstrate that the Au/PAN/p-Si/Al photodiode is a promising candidate for high-performance and wavelength-selective photodetector applications.

Interfacial engineering of Au/PAN/p-Si/Al Schottky photodiodes for UV photoresponse applications

期刊论文
发表日期：

2026年7月12日

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Ali Rıza Deniz,
Musa Erdoğan,
Zakir Çaldıran,
Gökhan Gök

摘要

In this study, an Au/PAN/p-Si/Al Schottky photodiode incorporating a 1-(2-pyridylazo)-2-naphthol (PAN) organic interfacial layer was fabricated and systematically investigated. The structural, optical, and electronic properties of the PAN thin film were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–Vis spectroscopy, and ultraviolet photoelectron spectroscopy (UPS). The PAN layer exhibited a semi-crystalline structure with nanoscale morphology, a wide optical band gap of approximately 3.7 eV, and high transparency in the visible region, making it suitable as an interfacial layer for optoelectronic applications. The electrical characteristics of the photodiode were evaluated based on current–voltage (I–V) measurements under dark and illumination conditions. The device exhibited clear rectifying behavior, confirming the formation of a Schottky junction. Key diode parameters, including ideality factor (n), barrier height (Φ_b), and series resistance (R_s), were extracted using thermionic emission and Norde methods. The results revealed that illumination significantly affected influences the junction properties, leading to an increase in saturation current and ideality factor, along with a reduction in barrier height. The optoelectronic performance of the device was further analyzed through photocurrent, responsivity (R), specific detectivity (D^*), and normalized photo-to-dark current ratio (NPDR) measurements. The photocurrent followed a power-law dependence on illumination intensity with α values approaching unity under reverse bias, indicating efficient carrier generation and transport. The device demonstrated a high detectivity on the order of ~ 10¹¹ Jones and a pronounced wavelength-dependent photoresponse, with superior performance under UV illumination. Transient measurements revealed stable and repeatable switching behavior with an ON/OFF ratio of ~ 50 and fast response times (τ_rise ≈ 0.2 s and τ_decay ≈ 0.15 s). In addition, long-term stability tests confirmed that the device maintains its performance after prolonged operation. Overall, the incorporation of the PAN interfacial layer significantly enhances the photodetection performance by improving charge separation, suppressing recombination, and modulating the Schottky barrier. These findings demonstrate that the Au/PAN/p-Si/Al photodiode is a promising candidate for high-performance and wavelength-selective photodetector applications.