Correlating the structural, optical and surface electronic properties of sputtered Co3O4 films.
AZEVEDO NETO, Nilton Francelosi; ALBANO, Luiz Gustavo Simão; RIBEIRO, Allan Victor; DALAN, Filipe Caldatto; PEREIRA, André Luis Jesus; ZANATTA, Antonio Ricardo; SILVA, José Humberto Dias da.
AZEVEDO NETO, Nilton Francelosi; ALBANO, Luiz Gustavo Simão; RIBEIRO, Allan Victor; DALAN, Filipe Caldatto; PEREIRA, André Luis Jesus; ZANATTA, Antonio Ricardo; SILVA, José Humberto Dias da.
Abstract: Cobalt tetraoxide (Co3O4) films were grown on indium tin oxide (ITO) substrates using a reactive direct current (DC) magnetron sputtering system. The oxygen flow rate was systematically varied from 5.0 to 7.0 standard cubic centimeter per minute (sccm) to investigate its influence on the structural, optical, and surface electronic properties of the films. X-ray diffraction (XRD) patterns and Raman spectroscopy confirmed the formation of the cubic spinel Co3O4 phase, exhibiting a decrease in lattice strain and an increase in crystallinity with the increase of the oxygen flow rate. A non-monotonic trend was observed in the intensity of the optical absorption band at 1.67 eV, which was found to be related to the non-linear changes in the Co3+/Co2+ ratio. Furthermore, Kelvin probe force microscopy (KPFM) measurements revealed that the oxygen flow rate enables the tuning of the film?s surface potential and work function. To quantitatively evaluate the relation among all measured variables, a statistical correlation analysis was conducted, revealing a strong negative correlation from the oxygen flow rate and lattice strain (r = -0.89), as well as between the Co3+/Co2+ ratio and the absorption coefficient at 1.67 eV (r = -0.82). These findings demonstrate the complex interplay of the reactive sputtering oxygen flow rate with the resulting physical properties of the Co3O4 films, providing valuable insights into how a single deposition parameter can be strategically exploited to tailor the material?s fundamental characteristics.
@article={003296571,author = {AZEVEDO NETO, Nilton Francelosi; ALBANO, Luiz Gustavo Simão; RIBEIRO, Allan Victor; DALAN, Filipe Caldatto; PEREIRA, André Luis Jesus; ZANATTA, Antonio Ricardo; SILVA, José Humberto Dias da.},title={Correlating the structural, optical and surface electronic properties of sputtered Co3O4 films},journal={Physica Scripta},note={v. 101, n. 12, p. 125907-1-125907-12 + supplementary materials},year={2026}}