Conductive and transparent multilayer films for low-temperature TiO2/Ag/SiO2 electrodes by E-beam evaporation with IAD

Po-Kai Chiu,Chao-Te Lee,Yi-Yan Chen,Chien-Nan Hsiao,Jer-Ren Yang,Wen-Hao Cho,Bo-Ming Huang,Donyau Chiang

doi:10.1186/1556-276x-9-35

Abstract

Conductive and transparent multilayer thin films consisting of three alternating layers (TiO2/Ag/SiO2, TAS) have been fabricated for applications as transparent conducting oxides. Metal oxide and metal layers were prepared by electron-beam evaporation with ion-assisted deposition, and the optical and electrical properties of the resulting films as well as their energy bounding characteristics and microstructures were carefully investigated. The optical properties of the obtained TAS material were compared with those of well-known transparent metal oxide glasses such as ZnO/Ag/ZnO, TiO2/Ag/TiO2, ZnO/Cu/ZnO, and ZnO/Al/ZnO. The weathering resistance of the TAS film was improved by using a protective SiO2 film as the uppermost layer. The transmittance spectra and sheet resistance of the material were carefully measured and analyzed as a function of the layer thickness. By properly adjusting the thickness of the metal and dielectric films, a low sheet resistance of 6.5 ohm/sq and a high average transmittance of over 89% in the 400 to 700 nm wavelength regions were achieved. We found that the Ag layer played a significant role in determining the optical and electrical properties of this film.

Highlights

The conduction electrons in a metal behave like a gas of nearly free electrons
In an effort to produce conductive and transparent substrates, multilayer coatings of the type dielectric material/metal/dielectric material (DMD) have been developed, as exemplified by ZnS/Ag/ZnS, ZnO/Ag/ ZnO, ITO/Ag/ITO, and ITO/CuAg/ITO (ITO, indium-tin oxide) [1,2,3,4]. These transparent multilayer films, which have low reflectance, good transparency, and high conductivity when prepared by low-temperature sputtering deposition, have been studied for developing functional materials such as heat mirrors [5,6]
Fabrication of TiO2/Ag/SiO2 transparent films Deposition techniques TiO2/Ag/ SiO2 (TAS) multilayers were fabricated by electron-beam (E-beam) evaporation with ion-assisted deposition ion-beam-assisted deposition (IAD) under a base pressure of 5 × 10−7 Torr

Summary

Introduction

The conduction electrons in a metal behave like a gas of nearly free electrons. Radiative surface modes can be excited at the boundary of the metal by using non-normal incident p-polarized light. In an effort to produce conductive and transparent substrates, multilayer coatings of the type dielectric material/metal/dielectric material (DMD) have been developed, as exemplified by ZnS/Ag/ZnS, ZnO/Ag/ ZnO, ITO/Ag/ITO, and ITO/CuAg/ITO (ITO, indium-tin oxide) [1,2,3,4]. These transparent multilayer films, which have low reflectance, good transparency, and high conductivity when prepared by low-temperature sputtering deposition, have been studied for developing functional materials such as heat mirrors [5,6]. The material composed of TiO2/Ag/ TiO2 (TAT) exhibited a transmittance of 68%, whereas that

Methods

Results

Conclusion