TY - JOUR
T1 - Effects of oxygen flow ratios and annealing temperatures on Raman and photoluminescence of titanium oxide thin films deposited by reactive magnetron sputtering
AU - Chung, C. K.
AU - Liao, M. W.
AU - Lai, C. W.
N1 - Funding Information:
This work is partially sponsored by National Science Council under grant No NSC 96-2628-E-006-080-MY3 . We pay our great thanks to the Center for Micro/Nano Science and Technology (CMNST) in National Cheng Kung University for the access of process and analysis equipment.
PY - 2009/12/31
Y1 - 2009/12/31
N2 - Titanium oxide (TiOx) thin films were deposited on the Si(100) substrates by direct-current reactive magnetron sputtering at 3-15 % oxygen flow ratios (FO2% = FO2/(FO2 + FAr) × 100%), and then annealed by rapid thermal annealing (RTA) at 350-750 °C for 2 min in air. The phase, bonding and luminescence behaviors of the as-deposited and annealed TiOx thin films were analyzed by X-ray diffraction (XRD), Raman spectroscopy and photoluminescence (PL) spectroscopy, respectively. The as-deposited TiOx films were amorphous from XRD and showed weak Raman intensity. In contrast, the distinct crystalline peaks of anatase and rutile phases were detected after RTA at 550-750 °C from both XRD and Raman spectra. A mixture of anatase and rutile phases was obtained by RTA at 3 FO2% and its amount increased with annealing temperature. Only the anatase phase was detected in the 6-15 FO2% specimens after RTA. The PL spectra of all post-annealed TiOx films showed a broad peak in visible light region. The PL peak of TiOx film at 3 FO2% at 750 °C annealing can be fitted into two Gaussian peaks at ~ 486 nm (2.55 eV) and ~ 588 nm (2.11 eV) which were attributed to deep-level emissions of oxygen vacancies in the rutile and anatase phases, respectively. The peak around 550 nm was observed at 6-15 FO2% which is attributed to electron-hole pair recombination from oxygen vacancy state in anatase phase to valence band. The variation of intensity of PL peaks is concerned with the formation of the rutile and anatase phases at different FO2% and annealing temperatures.
AB - Titanium oxide (TiOx) thin films were deposited on the Si(100) substrates by direct-current reactive magnetron sputtering at 3-15 % oxygen flow ratios (FO2% = FO2/(FO2 + FAr) × 100%), and then annealed by rapid thermal annealing (RTA) at 350-750 °C for 2 min in air. The phase, bonding and luminescence behaviors of the as-deposited and annealed TiOx thin films were analyzed by X-ray diffraction (XRD), Raman spectroscopy and photoluminescence (PL) spectroscopy, respectively. The as-deposited TiOx films were amorphous from XRD and showed weak Raman intensity. In contrast, the distinct crystalline peaks of anatase and rutile phases were detected after RTA at 550-750 °C from both XRD and Raman spectra. A mixture of anatase and rutile phases was obtained by RTA at 3 FO2% and its amount increased with annealing temperature. Only the anatase phase was detected in the 6-15 FO2% specimens after RTA. The PL spectra of all post-annealed TiOx films showed a broad peak in visible light region. The PL peak of TiOx film at 3 FO2% at 750 °C annealing can be fitted into two Gaussian peaks at ~ 486 nm (2.55 eV) and ~ 588 nm (2.11 eV) which were attributed to deep-level emissions of oxygen vacancies in the rutile and anatase phases, respectively. The peak around 550 nm was observed at 6-15 FO2% which is attributed to electron-hole pair recombination from oxygen vacancy state in anatase phase to valence band. The variation of intensity of PL peaks is concerned with the formation of the rutile and anatase phases at different FO2% and annealing temperatures.
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U2 - 10.1016/j.tsf.2009.09.076
DO - 10.1016/j.tsf.2009.09.076
M3 - Article
AN - SCOPUS:70449461507
VL - 518
SP - 1415
EP - 1418
JO - Thin Solid Films
JF - Thin Solid Films
SN - 0040-6090
IS - 5
ER -