| dc.description.abstract | In this study, we successfully fabricated large-area, well-ordered, and vertically aligned single-crystalline silicon nanotube arrays on (001) silicon substrates at room temperature using polystyrene nanosphere lithography combined with metal-assisted electrochemical etching. This method is a one-step, low-cost, and safe process. By adjusting the size of the nanospheres and the etching time, we could control the outer diameter and length of the silicon nanotubes, respectively. Subsequently, we deposited a nickel thin film onto the surface of the silicon nanotube structures via sputtering, followed by high-temperature annealing to produce nickel silicide nanotube arrays. The morphology and single-crystalline structure of the fabricated silicon nanotube structures and NiSi2 nanotube structures, as well as their high vertical alignment, were confirmed through SEM, TEM, and corresponding selected area electron diffraction (SAED) analysis.
Using a spectrometer, we measured the optical properties of the aforementioned structures. The results revealed that sputtering a nickel thin film onto the structure′s surface improved the silicon substrate′s light absorption in the near-infrared region. Moreover, after forming nickel silicide through high-temperature annealing, the light absorption further increased. Consequently, using nickel silicide as the basis, we used a 940 nm near-infrared light source to measure the photo-sensing properties of the fabricated silicon-based infrared photodetectors. These detectors exhibited self-powered sensing characteristics without the application of an external voltage. We analyzed and discussed the near-infrared responsivity, sensitivity, and response and recovery times of these photodetectors. | en_US |