Pinhole-resistant nanocrystalline rutile TiO2 photoelectrode coatings
Palmolahti, Lauri ; Ali-Löytty, Harri ; Hannula, Markku ; Saari, Jesse ; Wang, Weimin LU
; Tukiainen, Antti
; Lahtonen, Kimmo
and Valden, Mika
(2022)
In Acta Materialia
239.
- Abstract
Atomic layer deposited (ALD) TiO2 thin films have a wide range of applications in photonics which are, however, limited by the chemical instability of the amorphous as-deposited TiO2. Post-deposition annealing is required for improving the performance by inducing phase transitions and oxide defects. ALD precursor traces remaining in the TiO2 film affect the thermally-induced processes but the understanding of the effect of growth temperature on precursor traces in the film as well as on the thermally-induced processes is weak. In this study 30 nm ALD TiO2 was grown on Si wafer from tetrakis(dimethylamido)titanium and water at 100–200 °C. TiO2 was subsequently annealed in vacuum at... (More)
Atomic layer deposited (ALD) TiO2 thin films have a wide range of applications in photonics which are, however, limited by the chemical instability of the amorphous as-deposited TiO2. Post-deposition annealing is required for improving the performance by inducing phase transitions and oxide defects. ALD precursor traces remaining in the TiO2 film affect the thermally-induced processes but the understanding of the effect of growth temperature on precursor traces in the film as well as on the thermally-induced processes is weak. In this study 30 nm ALD TiO2 was grown on Si wafer from tetrakis(dimethylamido)titanium and water at 100–200 °C. TiO2 was subsequently annealed in vacuum at 200–500 °C. Increasing the growth temperature decreased the amount of N bearing precursor traces and thus makes the TiO2 more easily reducible. The reduction takes place simultaneously with the crystallization and formation of O1− defects. Vacuum annealing of TiO2 with less than 0.3 at% of N results in nanocrystalline rutile whereas samples with more N containing traces crystallized as microcrystalline anatase. Nanocrystalline rutile TiO2 was chemically stable and resistant to the dissolution at the grain boundaries under alkaline conditions making it a suitable material for protective photoelectrode coatings used in artificial photosynthesis.
(Less)
- author
- Palmolahti, Lauri
; Ali-Löytty, Harri
; Hannula, Markku
; Saari, Jesse
; Wang, Weimin
LU
; Tukiainen, Antti
; Lahtonen, Kimmo
and Valden, Mika
- organization
- publishing date
- 2022-10-15
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Artificial photosynthesis, Atomic layer deposition, Crystallization, Titanium dioxide
- in
- Acta Materialia
- volume
- 239
- article number
- 118257
- publisher
- Elsevier
- external identifiers
-
- scopus:85136479721
- ISSN
- 1359-6454
- DOI
- 10.1016/j.actamat.2022.118257
- language
- English
- LU publication?
- yes
- id
- f7505b89-4d13-4bd1-9b0b-971e6b7febd2
- date added to LUP
- 2024-01-12 14:19:26
- date last changed
- 2024-01-12 14:19:26
@article{f7505b89-4d13-4bd1-9b0b-971e6b7febd2,
abstract = {{<p>Atomic layer deposited (ALD) TiO<sub>2</sub> thin films have a wide range of applications in photonics which are, however, limited by the chemical instability of the amorphous as-deposited TiO<sub>2</sub>. Post-deposition annealing is required for improving the performance by inducing phase transitions and oxide defects. ALD precursor traces remaining in the TiO<sub>2</sub> film affect the thermally-induced processes but the understanding of the effect of growth temperature on precursor traces in the film as well as on the thermally-induced processes is weak. In this study 30 nm ALD TiO<sub>2</sub> was grown on Si wafer from tetrakis(dimethylamido)titanium and water at 100–200 °C. TiO<sub>2</sub> was subsequently annealed in vacuum at 200–500 °C. Increasing the growth temperature decreased the amount of N bearing precursor traces and thus makes the TiO<sub>2</sub> more easily reducible. The reduction takes place simultaneously with the crystallization and formation of O<sup>1−</sup> defects. Vacuum annealing of TiO<sub>2</sub> with less than 0.3 at% of N results in nanocrystalline rutile whereas samples with more N containing traces crystallized as microcrystalline anatase. Nanocrystalline rutile TiO<sub>2</sub> was chemically stable and resistant to the dissolution at the grain boundaries under alkaline conditions making it a suitable material for protective photoelectrode coatings used in artificial photosynthesis.</p>}},
author = {{Palmolahti, Lauri and Ali-Löytty, Harri and Hannula, Markku and Saari, Jesse and Wang, Weimin and Tukiainen, Antti and Lahtonen, Kimmo and Valden, Mika}},
issn = {{1359-6454}},
keywords = {{Artificial photosynthesis; Atomic layer deposition; Crystallization; Titanium dioxide}},
language = {{eng}},
month = {{10}},
publisher = {{Elsevier}},
series = {{Acta Materialia}},
title = {{Pinhole-resistant nanocrystalline rutile TiO<sub>2</sub> photoelectrode coatings}},
url = {{http://dx.doi.org/10.1016/j.actamat.2022.118257}},
doi = {{10.1016/j.actamat.2022.118257}},
volume = {{239}},
year = {{2022}},
}