TITLE:
Al-Doping Effect on the Surface Morphology of ZnO Films Grown by Reactive RF Magnetron Sputtering
AUTHORS:
Erica Pereira da Silva, Michel Chaves, Gilvan Junior da Silva, Larissa Baldo de Arruda, Paulo Noronha Lisboa-Filho, Steven Frederick Durrant, José Roberto Ribeiro Bortoleto
KEYWORDS:
ZnO Thin Films; Surface Morphology; RF Magnetron Sputtering
JOURNAL NAME:
Materials Sciences and Applications,
Vol.4 No.12,
December
6,
2013
ABSTRACT:
Zinc oxide (ZnO) and aluminum-doped zinc oxide (ZnO:Al) thin films were deposited onto glass and silicon substrates by RF magnetron sputtering using a zinc-aluminum target. Both films were deposited at a growth rate of 12.5 nm/min to a thickness of around 750 nm. In the visible region, the films exhibit optical transmittances which are greater than 80%. The optical energy gap of ZnO films increased from 3.28 eV to 3.36 eV upon doping with Al. This increase is related to the increase in carrier density from 5.9 × 1018 cm-3 to 2.6 × 1019 cm-3. The RMS surface roughness of ZnO films grown on glass increased from 14 to 28 nm even with only 0.9% at Al content. XRD analysis revealed that the ZnO films are polycrystalline with preferential growth parallel to the (002) plane, which corresponds to the wurtzite structure of ZnO.