TY - JOUR
T1 - X-ray photoelectron spectroscopy-based valence band spectra of passive films on titanium
AU - Eda, Yuzuki
AU - Manaka, Tomoyo
AU - Hanawa, Takao
AU - Chen, Peng
AU - Ashida, Maki
AU - Noda, Kazuhiko
N1 - Funding Information:
This work was supported by the Design & Engineering by Joint Inverse Innovation for Materials Architecture Project, Biable Materials Project, and Research Center for Biomedical Engineering, Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.
Publisher Copyright:
© 2022 The Authors. Surface and Interface Analysis published by John Wiley & Sons Ltd.
PY - 2022/8
Y1 - 2022/8
N2 - Titanium (Ti) is always covered by thin passive films. Thus, valence band (VB) spectra, obtained using X-ray photoelectron spectroscopy (XPS), are superpositions of the VB spectra of passive films and that of the metallic Ti substrate. In this study, to obtain the VB spectra only of passive films, angular resolution (for eliminating the substrate Ti contribution) and argon ion sputtering (for removing passive films) were used along with XPS. The passive film on Ti was determined to consist of a very thin TiO2layer with small amounts of Ti2O3, TiO, hydroxyl groups, and water with a thickness of 5.9 nm. The VB spectra of Ti were deconvoluted into four peak components: a peak at ~1 eV, attributed to the Ti metal substrate; a broad peak in the 3–10 eV range, mainly attributed to O 2p (~6 eV) and O 2p-Ti 3d hybridized states (~8 eV), owing to the π (non-bonding) and σ (bonding) orbitals in the passive oxide film; and a peak at ~13 eV, attributed to the 3σ orbital of O 2p as OH−or H2O. The VB region spectrum between approximately 3 and 14 eV from Ti is originating from the passive film on Ti. In particular, characterization of VB spectrum obtained with a takeoff angle of less than 24° is effective to obtain VB spectrum only from the passive film on Ti. The property as n-type semiconductor of the passive film on Ti is probably higher than that of rutile TiO2ceramics.
AB - Titanium (Ti) is always covered by thin passive films. Thus, valence band (VB) spectra, obtained using X-ray photoelectron spectroscopy (XPS), are superpositions of the VB spectra of passive films and that of the metallic Ti substrate. In this study, to obtain the VB spectra only of passive films, angular resolution (for eliminating the substrate Ti contribution) and argon ion sputtering (for removing passive films) were used along with XPS. The passive film on Ti was determined to consist of a very thin TiO2layer with small amounts of Ti2O3, TiO, hydroxyl groups, and water with a thickness of 5.9 nm. The VB spectra of Ti were deconvoluted into four peak components: a peak at ~1 eV, attributed to the Ti metal substrate; a broad peak in the 3–10 eV range, mainly attributed to O 2p (~6 eV) and O 2p-Ti 3d hybridized states (~8 eV), owing to the π (non-bonding) and σ (bonding) orbitals in the passive oxide film; and a peak at ~13 eV, attributed to the 3σ orbital of O 2p as OH−or H2O. The VB region spectrum between approximately 3 and 14 eV from Ti is originating from the passive film on Ti. In particular, characterization of VB spectrum obtained with a takeoff angle of less than 24° is effective to obtain VB spectrum only from the passive film on Ti. The property as n-type semiconductor of the passive film on Ti is probably higher than that of rutile TiO2ceramics.
KW - X-ray photoelectron spectroscopy
KW - passive film
KW - titanium
KW - valence band
UR - http://www.scopus.com/inward/record.url?scp=85128562118&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85128562118&partnerID=8YFLogxK
U2 - 10.1002/sia.7102
DO - 10.1002/sia.7102
M3 - Article
AN - SCOPUS:85128562118
SN - 0142-2421
VL - 54
SP - 892
EP - 898
JO - Surface and Interface Analysis
JF - Surface and Interface Analysis
IS - 8
ER -