Al2O3 and Sn/Al2O3 nanowires: fabrication and characterisation

Self-ordered anodised aluminium oxide membranes can be used as a base for the growth of different nanoarrays. In this reported work, an efficient and effective method is implemented to fabricate highly ordered alumina nanowires (ANWs) covered with a uniform shell of 12 ± 2 nm Sn nanoparticles (Sn/ANWs). A two-step anodisation process followed by a selective etching process was used to prepare highly ordered ANWs with diameters smaller than 36 nm. The thermal evaporation technique was used to ensure the deposition of a Sn nanoshell on the fabricated nanowires. The fabricated nanostructures were characterised by energy-dispersive X-ray spectroscopy, X-ray diffraction, field emission-scanning electron microscopy and an ultraviolet-visible-near-infrared spectrophotometer. Analysis of the scanning electron microscopy images showed that the etching rate is 0.73 nm/min and ANWs are obtained after etching the membrane for 110 min. The measured reflection spectra revealed that Sn/ANWs exhibit a redshift of the UV absorption band relative to the ANWs and a reflectance of nearly 100% in the near-infrared region. For optical comparison, glass slides were coated with Sn under the same conditions for 90 and 120 s. The reflection spectrum of the 120 s Sn-coated glass slide shows three modes at 210, 296 and 700 nm because of the excitation and interference of plasmonic waves.