Optical absorption and Photoluminescence in ultra thin silver and silver iodide films

Silver thin films in the thickness range 3-10 nm produced by thermal evaporation onto glass substrates were systematically iodized and carefully characterized by XRD, AFM and optical absorption and cw photoluminescence (PL) spectroscopy while the uniodized films are X-ray amorphous in view of their quasi-continuous nature and 2D islanded structure, briefly-iodized films showed characteristic beta AgI structure. Optical absorption spectra of uniodized Ag films show intense surface plasmon resonance (SPR) features with maxima at 440, 484 and 498 nm for the films of thickness 3, 5 and 10 nm. PL shows a thickness dependent emission suggesting the involvement of Frenkel defects in non-radiative recombination.