Comparative evaluation of V₂O₅/PANI nanocomposite photodetectors on silicon and FTO substrates

This study illustrates the pivotal importance of substrate selection in enhancing the structural, and optical characteristics of photodetector devices. V₂O₅/PANI composites were synthesized by a 6-h hydrothermal process at 180°C and subsequently coated onto two distinct substrates, silicon and FTO, utilizing a sputter coating approach. X-ray diffraction (XRD) studies revealed that the active layer placed on silicon exhibited distinct peaks of the orthorhombic V₂O₅ phase, but crystallinity was less evident on FTO, with the predominant PANI phase. FESEM and AFM investigations demonstrated a more homogenous and uniform surface on silicon, exhibiting reduced surface imperfections. Photoluminescence experiments indicated enhanced and more uniform emission within the silicon samples’ 450–650 nm spectrum, signifying superior charge transfer efficiency. At the photodetector performance level, I–V tests indicated that the films formed on silicon had markedly enhanced performance, with a photocurrent of (I_{F (+5)} Light = 3113µA) versus a dark current (I_{F (-5)} dark = 1689 µA), with a better on/off ratio (0.26 /0.19 s). They documented a photoresponsivity of 0.27 A/W, a photodetectivity of 1.26 × 10²⁰ Jones, and an external quantum efficiency (EQE) of 109%. The results demonstrate that employing a silicon substrate boosts the quality of the composite nanofilm and optimizes the separation and transport dynamics of photocarriers, hence benefiting the performance of the V₂O₅/PANI hybrid photodetector. The research underscores the significance of substrate selection as a pivotal factor in enhancing the structural, optical, and electrical characteristics of performance photodetector devices.