High performance piezoresistive response of nanostructured ZnO/Ag thin films for pressure sensing applications

THIN SOLID FILMS

卷:691

Article

Ferreira, Armando¹  Silva, Joao Paulo¹  Rodrigues, Rui¹  Martin, Nicolas²  Lanceros-Mendez, Senentxu^3,4  Vaz, Filipe¹ 

[1] Univ Minho, Ctr Fis, P-4710057 Braga, Portugal

[2] Univ Bourgogne Franche Comte, Inst FEMTO ST, UMR CNRS 6174, 15B Ave Montboucons, F-25030 Besancon, France

[3] Basque Ctr Mat Applicat & Nanostruct, BCMat, UPV EHU Sci Pk, Leioa 48940, Spain

[4] Basque Fdn Sci, Ikerbasque, Bilbao 48013, Spain

关键词: Sensors;    Zinc oxide;    Silver;    Gauge factor;    Dc magnetron sputtering;    Electromechanical properties;   

DOI  :  10.1016/j.tsf.2019.137587

来源: Elsevier

【 摘 要 】

This work reports on the preparation and characterization of zigzag nanostructured silver (Ag) doped zinc oxide (ZnO) films in order to improve piezoresistive response for pressure sensor applications. ZnO/Ag thin films were prepared by Glancing Angle Deposition (GLAD) from a metallic zinc (Zn) target DC sputtered in Ar + O-2 atmosphere. The target was customized with different amounts of Ag pellets, symmetrically distributed along the preferential erosion area. It is shown that increasing the Ag content from O to 36 at.% in the ZnO/Ag system leads to a decrease of the electrical resistivity from 2.95 Omega cm to 1.52 x 10(-5) Omega cm. The structural characterization of the thin films shows an evolution of the preferential growth, changing from a polycrystalline ZnO hexagonal-like structure, confirmed by the presence of dominant ZnO (002) and ZnO (101) diffraction peaks, to a Ag cubic (fcc)-like structure, as evidenced by the Ag (111), (200) and (220) diffraction peaks. The values of the gauge factor show a strong contribution both from Ag as well as from the zigzag nanostructure to the piezoresistive sensitivity of the films, in particular for Ag concentrations lower than 30 at.%. The tunneling distance between pairs of Ag conducive nanoregions was calculated for the different samples and in three different deformation regions, in order to evaluate its influence on the piezoresistive sensitivity. The results show that a longer distance between Ag particles, which varies from 0.1 to 10 nm, enhances the gauge factor, which ranges from 8 +/- 1 to 120 +/- 3, respectively.

【 授权许可】

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