Nb seeding이 Ag 박막 성장모드에 미치는 영향에 대한 열역학적인 고찰

Abstract

For low-emissivity application on window glass, coalescence of thin film silver islands is crucial for high transmittance in the visible and high reflectance in the infrared. It is well known that the underlayer affects the growth mode. In this work, the effect of the underlayer on the growth of silver films deposited by filtered cathodic vacuum arc is discussed. While a nominal 0.1 nm niobium underlayer has promoted the coalescence of silver islands, a 0.2 nm layer did not show these features. From a thermodynamic approach, Nb seeding less one monolayer is considered to reduce the surface energy between the silver atoms and <TEX>$Nb/TiO_2$</TEX> surface, resulting the change of its growth from 3D islands to 2D-layer modes. If the seed layer exceeds one monolayer, however, a rougher surface is formed because the surface energy of Nb itself is superior to that of <TEX>$Nb-TiO_2$</TEX>. The onset of silver layer on the roughened Nb surface is required more silver.