Magnetron Sputtering Technique Grown Silicon Nanowires: Impact of Growth Time

Silicon (Si) nanowires (NWs) were effectively fabricated on a gold-coated Si substrate at 550°C using a radio-frequency (RF) magnetron sputtering process. The growth time was carefully adjusted to 30, 45, 60, and 75 min to accurately examine its effect on the NWs characteristics. Field emission scanning electron microscopy disclosed the successful growth of uniform, high-aspect-ratio NWs, demonstrating a direct link between their length and growth time, with a progressive elongation observed from 30 to 75 min. Fourier-transform infrared spectroscopy confirmed the chemical structure through distinct absorption peaks at approximately 611 cm–1 (representing Si-Si stretching vibrations) and around 1107 cm–1 (for Si–O–Si asymmetric stretching vibrations), confirming the core-shell formation of crystalline Si-NWs with a native oxide surface layer. Optically, photoluminescence spectroscopy revealed an intense emission peak in the visible region, ascribed to defect-mediated transitions. Separately, optical reflectivity analysis showed notably low light reflectance across a wide spectrum, underscoring the remarkable ability of the NWs to trap light. X-ray diffraction measurements confirmed the phase purity and high crystallinity of the grown Si-NWs. High-resolution transmission electron microscopy also established their crystalline nature and exact growth orientation. The synergy of their superior light-trapping capability, crystalline structure, and tunable dimensions renders these Si-NWs ideal for high-performance photovoltaics.