Magnetron sputtering process of carbon-doped α-Fe2O3 thin films for photoelectrochemical water splitting

Mao Chia Huang, Wen Sheng Chang, Jing Chie Lin, Yu Hsu Chang, Ching Chen Wu

Research output: Contribution to journalArticlepeer-review

49 Scopus citations

Abstract

Thin films of α-Fe2O3 doped with carbon have been fabricated on F-doped SnO2 glass substrate by magnetron sputtering process via DC power on the pure Fe target (99.99%) combined with RF power on the pure graphite target (99.99%). The influences of RF power (0, 40, 80 and 120 W) on optical, structural and photoelectrochemical (PEC) characteristics have been investigated. The as-obtained samples after annealing in Ar ambient were analyzed by scanning electron microscopy, X-ray diffraction (XRD), Raman spectra, UV-visible spectra and electrochemical analysis. After annealing, all samples revealed only hematite characteristics in XRD pattern and Raman spectra. Thickness of annealed thin films was ∼350 nm measured via SEM cross-section image. The optical band gap and carrier concentration of samples were in the range of 2.13-2.16 eV and 6.28 × 1017 to 3.11 × 1018 cm-3, respectively. Based upon our observations, the 4.56 at.% carbon-doped α-Fe2O3 thin film deposited via 80 W RF power has a better PEC response with photocurrent density of ∼1.18 mA/cm2 at 0.6 V vs. SCE. This value was about three times higher than the un-doped film (0 W of RF power, reference sample). Observed higher photocurrent density was likely due to a suitable carbon-doping concentration causing a higher carrier concentration.

Original languageEnglish
Pages (from-to)176-182
Number of pages7
JournalJournal of Alloys and Compounds
Volume636
DOIs
StatePublished - 5 Jul 2015

Keywords

  • Keywords Carbon-doped
  • Magnetron sputtering process
  • Photoelectrochemistry (PEC)
  • Water splitting
  • α-FeO (Hematite)

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