Fabrication of highly efficient resonant structure assisted ultrathin artificially stacked Ag/ZnS/Ag multilayer films for color filter applications

Abstract

We introduce a novel strategy for the fabrication of mechanically and thermally stable highly efficient resonant structure assisted ultrathin artificially stacked Ag/ZnS/Ag multilayer films on cleaned glass substrates using the thermal evaporation technique. The application of fabricated color filters has been studied in the visible range. These multilayers have good adhesion to each other and to the glass substrate, resulting in mechanical and thermal stability. The stability has been examined by the “Scotch-tape” test and the ultrasonication process at 37 kHz frequency and at 40 °C temperature as well as by thermogravimetric analysis (TGA). The results of the structural analysis, surface morphology and atomic force microscopy of these filters confirm the good crystallinity with a low value of surface roughness. The effect of thickness of artificially stacked metal (Ag) and dielectric (ZnS) layers has been examined in terms of optical properties by several spectroscopic techniques. These ingenious filters exhibit a large and deep stop band in the visible wavelength region. Thus blue, green and red color filters, centered at 460, 540 and 620 nm having bandwidths of about 25, 44 and 35 nm, respectively, were achieved. Moreover, the statistical outcomes of all the three filters (blue, green and red) show that the peak transmission efficiencies are consistently 73%, 70% and 63%, respectively. Additionally, the effect of different angles of incidence on the transmittance spectra has also been presented. Hence, the obtained results strongly suggest that these filters can be potentially used for tuning the color of optical filters according to the desired applications.