Fluorine-doped ZnO transparent conducting thin films prepared by radio frequency magnetron sputtering

Fluorine-doped ZnO transparent conducting thin films were prepared by radio frequency magnetron sputtering at 150 degrees C on glass substrate. Thermal annealing in vacuum was used to improve the optical and electrical properties of the films. X-ray patterns indicated that (002) preferential growth was observed. The grain size of F-doped ZnO thin films calculated from the full-width at half-maximum of the (002) diffraction lines is in the range of 18-24 nm. The average transmittance in visible region is over 90% for all specimens. The specimen annealed at 400 degrees C has the lowest resistivity of 1.86 x 10(-3) Omega cm, the highest mobility of 8.9 cm(2) V(-1) s(-1), the highest carrier concentration of 3.78 x 10(20) cm(-3), and the highest energy band gap of 3.40 eV. The resistivity of F-doped ZnO thin films increases gradually to 4.58 x 10(-3) Omega cm after annealed at 400 degrees C for 4h. The variation of the resistivity is slight. (C) 2010 Elsevier B.V. All rights reserved.