The effect of annealing on Al-doped ZnO films deposited by RF magnetron sputtering method for transparent electrodes

摘要

In this study, transparent conducting Al-doped zinc oxide (AZO) films with a thickness of 150nm were prepared on Corning glass substrates by the RF magnetron sputtering with using a ZnO:Al (Al_2O_3: 2 wt.%) target at room temperature. This study investigated the effects of the post-annealing temperature and the annealing ambient on the structural, electrical and optical properties of the AZO films. The films were annealed at temperatures ranging from 300 to 500 ℃ in steps of 100 ℃ by using rapid thermal annealing equipment in oxygen. The thicknesses of the films were observed by field emission scanning electron microscopy (FE-SEM): their grain size was calculated from the X-ray diffraction (XRD) spectra using the Scherrer equation. XRD measurements showed the AZO films to be crystallized with strong (002) orientation as substrate temperature increases over 300 ℃. Their electrical properties were investigated by using the Hall measurement and their transmittance was measured by UV-vis spectrometry. The AZO film annealed at the 500 ℃ in oxygen showed an electrical resistivity of 2.24 × 10~(-3)Ω cm and a very high transmittance of 93.5% which were decreased about one order and increased about 9.4%, respectively, compared with as-deposited AZO film.