Structural and optical evaluation of pristine and partially iodized ag thin films

Abstract

Pristine and partially iodized noble metal thin films are of interest in plasmonic, ‘plexitonic’ (involving Plasmon-exciton interaction and transition) and nanophotonic applications as well as potential substrates for SERS. It is crucial to basically characterize such films for optimization and implementation of structures for specific practical applications. Iodization offers an attractive, simple and effective experimental procedure to modify the surface of noble metal films and also to grow semiconductor nanostructures. Interestingly one can observe the development of excitonic and fundamental electronic band structure of the semiconductor which is AgI in the present case. In this paper we focus on structural and optical characterization of (a) <30 nm thick Ag films obtained by thermal evaporation and (b) the same Ag films surface-modified by partial iodization. The Structural properties, the crystal structure, Surface morphology and chemical composition of the deposited Ag films were studied by X-Ray diffraction (XRD), Field Emission Scanning electron microscopy (FESEM). XRD Pattern showed that the films had preferred orientation along (111) of the face centered cubic (fcc) structure. The mechanical properties (The intrinsic stress, Dislocation density, grain size) are also calculated. The optical properties pristine and partially iodized Ag films of were investigated by measuring the absorbance from 300 to 800 nm.