Al-Doping Effect on the Surface Morphology of ZnO Films Grown by Reactive RF Magnetron Sputtering

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

Group of Advanced Materials, S?o Paulo State University-UNESP, Bauru, Brazil.
Technological Plasmas Laboratory, S?o Paulo State University-UNESP, Sorocaba, Brazil.

DOI: 10.4236/msa.2013.412096                

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.

Keywords

ZnO Thin Films; Surface Morphology; RF Magnetron Sputtering

Conflicts of Interest

The authors declare no conflicts of interest.

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