Open Access Nano Express

Study of a sandwich structure of transparent conducting oxide films prepared by electron beam evaporation at room temperature

Po Kai Chiu12*, Wen Hao Cho1, Hung Ping Chen1, Chien Nan Hsiao1 and Jer Ren Yang2

Author Affiliations

1 Instrument Technology Research Center, National Applied Research Laboratories, Taipei, Taiwan

2 Institute of Materials Science and Engineering, National Taiwan University, Taipei, 10617, Taiwan

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Nanoscale Research Letters 2012, 7:304  doi:10.1186/1556-276X-7-304

Published: 14 June 2012

Abstract

Transparent conducting ZnO/Ag/ZnO multilayer electrodes having electrical resistance much lower than that of widely used transparent electrodes were prepared by ion-beam-assisted deposition (IAD) under oxygen atmosphere. The optical parameters were optimized by admittance loci analysis to show that the transparent conducting oxide (TCO) film can achieve an average transmittance of 93%. The optimum thickness for high optical transmittance and good electrical conductivity was found to be 11 nm for Ag thin films and 40 nm for ZnO films, based on the admittance diagram. By designing the optical thickness of each ZnO layer and controlling process parameters such as IAD power when fabricating dielectric-metal-dielectric films at room temperature, we can obtain an average transmittance of 90% in the visible region and a bulk resistivity of 5 × 10−5 Ω-cm. These values suggest that the transparent ZnO/Ag/ZnO electrodes are suitable for use in dye-sensitized solar cells.

Keywords:
ZnO; E-beam; Ion-beam-assisted deposition (IAD); Room temperature; Transparent conducting oxide (TCO)