| dc.description.abstract | The present study has demonstrated the successful fabrication of density-, size- and shape-controllable Si nanostructure arrays on Si substrates of different orientation by using plasma modified nanosphere lithography and anisotropic wet etching process. The morphologies, crystal structures, compositions, optical and surface properties of the Si nanostructure arrays produced have been systematically investigated by SEM, AFM, TEM, SAED, EDS, XPS, UV-Vis and contact angle analyses.
For the fabrication of periodic Si nanohole arrays, we take advantage of O2 plasma RIE treatment, which allows us simultaneously to adjust the diameter of PS nanospheres template and to form a passivation a-SiOx layer on Si serving as the etching mask. The shapes, sizes and positions of Si nanoholes that formed on Si substrates could be tuned by adjusting the diameters of the colloidal nanospheres and the KOH etching time. On the other hand, by combining the plasma modified nanosphere lithography, selective chemical etching process or metal silicide formation, large-area, size- and height-tunable Si nanocone arrays were also successfully fabricated on (001), (110) and (111)Si substrates in this study. From the water contact angle measurements, the surface of HF-treated Si nanohole and nanocone arrays exhibited hydrophobic characteristics. The hydrophobic behavior of Si nanostructures could be explained by the Cassie model. Furthermore, UV-Vis spectroscopic measurements revealed that the nanostructured Si surfaces exhibit strong antireflection properties.The enhanced antireflection properties can be attributed to the light trapping effect resulting from the nanostructure-arrayed Si surfaces.
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