Effective Density of Tantalum Oxide Thin Film by Reactive DC Magnetron Sputtering for All-Solid-State Switchable Mirror

TLDR: In this article, an all-solid-state switchable mirror was fabricated by magnetron sputtering, and a relationship between density and electrochemical properties of Ta 2 O 5 thin film was investigated to improve the optical switching property of the device.

Abstract: We have fabricated an all-solid-state switchable mirror as a type of smart window by magnetron sputtering. The multilayer structure of Mg4Ni/Pd/Ta 2 O 5 /WO 3 /indium tin oxide/glass is included in the device. Each material of Mg 4 Ni, Pd, Ta 2 O 5 , and WO 3 in the device plays optical switching, proton injector, solid electrolyte, and ion storage, respectively. A relationship between density and electrochemical property of Ta 2 O 5 thin film deposited by reactive dc magnetron sputtering was investigated to improve the optical switching property of the device. Ta 2 O 5 thin film with a density of 3.8 g/cm 3 had better electrochemical property than that with other densities. The transmittance at a wavelength of 670 nm of the device using Ta 2 O 5 thin film with a density of 3.8 g/cm 3 was reached from 0.1% (reflective state) to 46% (transparent state) within 20 s by applying voltage. We suggest that the optical switching property of the device was affected by the density of Ta 2 O 5 thin film.