Title :
THz time-domain spectroscopy of nanometric-thick gold layers
Author :
Garet, F. ; Duvillaret, L. ; Coutaz, J.-L.
Author_Institution :
Lab. of Microwaves & Characterization, Savoy Univ., Le Bourget du Lau, France
fDate :
27 Sept.-1 Oct. 2004
Abstract :
Using THz time-domain spectroscopy (THz TDS), we study the far infrared (0.1-1.8 THz) response of evaporated gold films whose thicknesses spread from 1.5 up to 30 nm. In this frequency domain, free carriers mainly dictate the optical properties of metallic materials. These ultra thin films are composed of islands that are in contact when the thickness is larger than a critical value, namely the percolation threshold, leading to a metallic response for those thicknesses. Well below this threshold, the islands are completely separated and no electric conduction is allowed: the films behave as dielectric layers. Around the critical thickness, percolation-type conductivity is observed. THz TDS permits to clearly observe these 3 regimes and to determine the complex refractive index of ultra thin gold layers in the far infrared.
Keywords :
dielectric thin films; discontinuous metallic thin films; frequency-domain analysis; gold; nanostructured materials; refractive index; submillimetre wave spectra; 0.1 to 1.8 THz; 1.5 to 30 nm; Au; THz time-domain spectroscopy; dielectric layers; evaporated gold films; far infrared response; free carriers; frequency domain analysis; metallic materials; nanometric thick gold layers; optical properties; percolation type conductivity; refractive index; ultra thin films; Conducting materials; Dielectric thin films; Frequency domain analysis; Gold; Infrared spectra; Optical films; Optical refraction; Optical variables control; Spectroscopy; Time domain analysis;
Conference_Titel :
Infrared and Millimeter Waves, 2004 and 12th International Conference on Terahertz Electronics, 2004. Conference Digest of the 2004 Joint 29th International Conference on
Print_ISBN :
0-7803-8490-3
DOI :
10.1109/ICIMW.2004.1422166
