Effect of blocking layer on achieving low sheet resistances in low-E multilayer structures

Abstract

Low-emissivity films consisting of a metal oxide/Ag/metal oxide structure improve the thermal insulation performance of windows. Deposition of an oxide layer on top of the Ag layer requires either the insertion of a blocking layer (BL) or the sputtering deposition of an oxide target under an argon atmosphere. In this study, we carried out a sequential sputtering deposition method for inserting a BL to achieve both high visible-light transmittance and low sheet resistance. The effects of metallic and oxide BLs on the sheet resistances were investigated, and metallic BLs were confirmed to cause an increase in sheet resistance due to the diffusion of metal atoms into the Ag layer. Oxide BLs deposited under low oxygen concentrations maintained the low sheet resistance. The most significant result was obtained with a TiO x BL deposited under 2.9% oxygen, which prevented an increase in sheet resistance even after the deposition of the top layer (TL). By optimizing the thickness of the TL, high visible-light transmittance and low sheet resistance were achieved in a glass/TiO2/ZnO/Ag/TiO x /ZnO multilayer. Thus, high-performance multilayers could be fabricated by selecting an appropriate BL, which is beneficial for the industrial fabrication of low-E films.