Antireflection coatings (ARC), not only reduce the reflection of the incident radiation but also protect the surface from environmental degradations. In present study, three- layer design was theoretically calculated and experimentally realized on the surface of lead chalcogenide, which had high refractive characteristics. First the theoretical designs of three- layers of different dielectric materials (i.e., ZnSe, SnO2, SiO and MgF2) were simulated using optical matrix approach. Subsequently, the developed designs were experimentally produced on lead sulfide thin films using thermal evaporation technique. The efficiency of the designs was evaluated for 1500-2400 nm spectral range and found that the design comprising ZnSe-SiO-MgF2 had 23% better performance than ZnSe-SnO2-MgF2, besides consistent coating adhesion and morphology. The difference between theoretical and experimental results was less than 10 and 16 % for ZnSe-SiO-MgF2 and ZnSe-SnO2-MgF2, respectively.

Abstract: Soldering electrical contacts to gold thin films is a matter of consideration due to high soldering temperature, restricted wetting, excessive scavenging and low strength offered by most of the common soldering alloys. Indium alloys offer certain benefits for gold soldering justifying their increased cost. In the present study, hypo-, hyper- and eutectic In-Ag solder were prepared and investigated for compositional and structural homogeneity, soldering temperature, contact angle, spreading factor, scavenging zone and scavenging phase (i.e. Auln2). It was found that addition of silver (-3.5%) ameliorated the above mentioned characteristics for better control of soldering practice with gold thin films besides lowering the soldering temperature.