Long-range-ordered Ag nanodot arrays grown on GaAs substrate using nanoporous alumina mask

With more and more attention given to the plasmonic nanostructures enhancing light trapping of solar cells, the fabrication of metal nanostructures becomes more and more important. In this work, we fabricated porous anodic alumina on SiO2/GaAs substrate and obtained periodic Ag nanodots with hemispherical shape by electron beam evaporation. During the experiments, it was found that the properties of barrier layers of porous anodic alumina fabricated on SiO2/GaAs and SiO2/Si substrates after pore-widening are different. The through-hole porous anodic alumina film on SiO2/GaAs substrate cannot be obtained after a long pore-widening process. The additional Ar ion bombardment against the samples was needed in our experiments to get the through-hole porous anodic alumina films on SiO2/GaAs substrate.