The light detection performance of Al/VNPB/n-Si Schottky photodetectors for a wide-range spectrum

Abstract

A novel organic–inorganic Schottky photodetector incorporating a N4, N4′-di(Naphthalen-1-yl)-N4, N4′-bis(4-vinylphenyl)biphenyl-4,4′-diamine (VNPB) thin film interlayer was fabricated and systematically characterized. The Al/VNPB/n-Si Schottky photodetectors were investigated using UV–Vis spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM), revealing strong visible light absorption and high crystallinity. Electrical measurements under varying illumination intensities demonstrated enhanced rectification and significant photocurrent generation, attributed to thermionic emission and efficient photocarrier formation. Under solar illumination (20–100 mW/cm2), the device demonstrated strong photocurrent generation, high photosensitivity (22.05–80.58), responsivity up to 2.18 A/W, and detectivity values on the order of 1010 Jones, confirming efficient low-noise photodetection. The device exhibited high photosensitivity, responsivity, and specific detectivity across a broad spectral range (351–1600 nm), with peak performance at 600 nm, where a maximum responsivity of 0.0366 A/W, an external quantum efficiency of ∼75%, and a detectivity of 6.11×109 Jones were achieved. In addition, strong near-infrared performance was observed at 1000 nm, with a photosensitivity of 4.85 and a detectivity of 5.76×109 Jones. Compared to oxide-based photodetectors, the Al/VNPB/n-Si architecture demonstrated superior optoelectronic performance, positioning VNPB as a promising interfacial material for next-generation photodetection technologies.