Influence of lithium doping on the structural and electrical characteristics of ZnO thin films

Thin films of undoped and lithium-doped Zinc oxide, (Zn1−xLix)O; x = 0, 0.05, 0.10 and 0.20 were prepared by sol–gel method using spin-coating technique on silicon substrates [(111)Pt/Ti/SiO2/Si)]. The influence of lithium doping on the structural, electrical and microstructural characteristics have been investigated by means of X-ray diffraction, leakage current, piezoelectric measurements and scanning electron microscopy. The resistivity of the ZnO film is found to increase markedly with low levels (x ≤ 0.05) of lithium doping thereby enhancing their piezoelectric applications. The transverse piezoelectric coefficient, e31⁎ has been determined for the thin films having the composition (Zn0.95Li0.05)O, to study their suitability for piezoelectric applications. - Highlights: ► Preferentially c-axis oriented (Zn1−xLix)O films were spin-coated on glass. ► (Zn1−xLix)O thin films exhibit dense columnar microstructure. ► Low levels of lithium doping, increases the electrical resistivity of ZnO thin films. ► (Zn1−xLix)O thin films show high values of transverse piezoelectric coefficient, e⁎31.