%0 Journal Article
%T Nanostructure and Optical Properties of Silver Helical Pentagon Nanosculptured Thin Films
%A Hadi Savaloni
%A Fatemh Haydari-Nasab
%A Mariam Malmir
%J Advances in Condensed Matter Physics
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/857680
%X Silver helical pentagon shaped nanosculptured thin films (HPNSTFs) were produced using oblique angle deposition method in conjunction with the rotation of sample holder under controlled conditions. The -polarization extinction spectra obtained at different azimuthal angles ( ) and low incidence angle (i.e., ) from the Ag (HPNSTF) did not show significant change in the plasmon peak position, while at higher incidence angle (i.e., ) a blue shift appeared for the broad peak which was observed for lower incidence angle (i.e., ) and occurred at lower wavelength. In case of -polarized light a very broad peak was obtained for the incidence angle and for different angles and when compared with the lower incidence angle results it can be concluded that it is gone under a red shift. Polar diagrams of the samples showed slight anisotropy that should be due to high symmetry of the pentagon helical structure. 1. Introduction Sculptured thin films (STFs) are columnar (range between 1 and 100£¿nm) thin films deposited on substrate with controlled azimuthal rotation, , and tilt angle, , by a method known as oblique angle deposition (OAD) ( ) or glancing angle deposition (GLAD) ( ) [1]. The structure of STFs consists of rough surface with a much higher void fraction than the films produced using conventional deposition method (i.e., deposition at normal vapor incident angle). Hence, these nanostructures especially the metallic nanostructures with specific properties dependent on their size have created an interesting research environment for scientists in different fields of application like biomedicine [2¨C6], antibacterial [7], optics [8¨C11], and other fields of science. Polygonal helical sculptured thin films have been subject to investigation during the last few years. Hodgkinson was first to report on these films in 2004 [12] theoretically and experimentally, then Van Popta et al. [13] reported on double-handed circular Bragg phenomena in polygonal helix thin films and the next major advance was made by Dixit and Lakhtakia [14]. Kennedy et al. [15] by using GLAD technique fabricated tetragonal square spiral photonic crystals. Optical properties of square gold nanospirals have been investigated numerically by Abdeddaim et al. [16]. Robbie and Brett [17] produced sculptured thin films of different shapes (e.g., slanted nanorods, zigzag, and helices) using the GLAD technique. Experiments have demonstrated that the plasmon peak depends strongly on the morphology and assembly of the nanoparticles, such as diameter [18], aspect ratio [19], shape [20], or assembly of array
%U http://www.hindawi.com/journals/acmp/2014/857680/