Fabricating Si Nanowires with Precisely Controlled Diameter and Spacing

Due to their unique optical and electronic properties, Si nanowires are the building blocks in various applications, including nanoelectronics, catalysis, and sensors. Nanowires with different diameters, spacing, and length are often required for these functional devices to achieve optimal performance. In this work, we demonstrate the large-scale synthesis of vertically aligned, hexagonally packed Si nanowires with precisely controlled diameter and spacing. Nanosphere lighography and metal-assisated chemical etching are combined to prepare nanowires with diameters between 100 to 500 nm. Nanowire diameters are dictated by the SiO₂ nanopheres used for spin-coating, while their spacing is controlled by using different parameters during spin-coating, including spin speed and time.