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Optimization of Photogenerated Charge Carrier Lifetimes in ALD Grown TiO(2) for Photonic Applications
Titanium dioxide (TiO(2)) thin films are widely employed for photocatalytic and photovoltaic applications where the long lifetime of charge carriers is a paramount requirement for the device efficiency. To ensure the long lifetime, a high temperature treatment is used which restricts the applicabili...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7466613/ https://www.ncbi.nlm.nih.gov/pubmed/32784961 http://dx.doi.org/10.3390/nano10081567 |
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author | Khan, Ramsha Ali-Löytty, Harri Saari, Jesse Valden, Mika Tukiainen, Antti Lahtonen, Kimmo Tkachenko, Nikolai V. |
author_facet | Khan, Ramsha Ali-Löytty, Harri Saari, Jesse Valden, Mika Tukiainen, Antti Lahtonen, Kimmo Tkachenko, Nikolai V. |
author_sort | Khan, Ramsha |
collection | PubMed |
description | Titanium dioxide (TiO(2)) thin films are widely employed for photocatalytic and photovoltaic applications where the long lifetime of charge carriers is a paramount requirement for the device efficiency. To ensure the long lifetime, a high temperature treatment is used which restricts the applicability of TiO(2) in devices incorporating organic or polymer components. In this study, we exploited low temperature (100–150 °C) atomic layer deposition (ALD) of 30 nm TiO(2) thin films from tetrakis(dimethylamido)titanium. The deposition was followed by a heat treatment in air to find the minimum temperature requirements for the film fabrication without compromising the carrier lifetime. Femto-to nanosecond transient absorption spectroscopy was used to determine the lifetimes, and grazing incidence X-ray diffraction was employed for structural analysis. The optimal result was obtained for the TiO(2) thin films grown at 150 °C and heat-treated at as low as 300 °C. The deposited thin films were amorphous and crystallized into anatase phase upon heat treatment at 300–500 °C. The average carrier lifetime for amorphous TiO(2) is few picoseconds but increases to >400 ps upon crystallization at 500 °C. The samples deposited at 100 °C were also crystallized as anatase but the carrier lifetime was <100 ps. |
format | Online Article Text |
id | pubmed-7466613 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-74666132020-09-14 Optimization of Photogenerated Charge Carrier Lifetimes in ALD Grown TiO(2) for Photonic Applications Khan, Ramsha Ali-Löytty, Harri Saari, Jesse Valden, Mika Tukiainen, Antti Lahtonen, Kimmo Tkachenko, Nikolai V. Nanomaterials (Basel) Article Titanium dioxide (TiO(2)) thin films are widely employed for photocatalytic and photovoltaic applications where the long lifetime of charge carriers is a paramount requirement for the device efficiency. To ensure the long lifetime, a high temperature treatment is used which restricts the applicability of TiO(2) in devices incorporating organic or polymer components. In this study, we exploited low temperature (100–150 °C) atomic layer deposition (ALD) of 30 nm TiO(2) thin films from tetrakis(dimethylamido)titanium. The deposition was followed by a heat treatment in air to find the minimum temperature requirements for the film fabrication without compromising the carrier lifetime. Femto-to nanosecond transient absorption spectroscopy was used to determine the lifetimes, and grazing incidence X-ray diffraction was employed for structural analysis. The optimal result was obtained for the TiO(2) thin films grown at 150 °C and heat-treated at as low as 300 °C. The deposited thin films were amorphous and crystallized into anatase phase upon heat treatment at 300–500 °C. The average carrier lifetime for amorphous TiO(2) is few picoseconds but increases to >400 ps upon crystallization at 500 °C. The samples deposited at 100 °C were also crystallized as anatase but the carrier lifetime was <100 ps. MDPI 2020-08-10 /pmc/articles/PMC7466613/ /pubmed/32784961 http://dx.doi.org/10.3390/nano10081567 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Khan, Ramsha Ali-Löytty, Harri Saari, Jesse Valden, Mika Tukiainen, Antti Lahtonen, Kimmo Tkachenko, Nikolai V. Optimization of Photogenerated Charge Carrier Lifetimes in ALD Grown TiO(2) for Photonic Applications |
title | Optimization of Photogenerated Charge Carrier Lifetimes in ALD Grown TiO(2) for Photonic Applications |
title_full | Optimization of Photogenerated Charge Carrier Lifetimes in ALD Grown TiO(2) for Photonic Applications |
title_fullStr | Optimization of Photogenerated Charge Carrier Lifetimes in ALD Grown TiO(2) for Photonic Applications |
title_full_unstemmed | Optimization of Photogenerated Charge Carrier Lifetimes in ALD Grown TiO(2) for Photonic Applications |
title_short | Optimization of Photogenerated Charge Carrier Lifetimes in ALD Grown TiO(2) for Photonic Applications |
title_sort | optimization of photogenerated charge carrier lifetimes in ald grown tio(2) for photonic applications |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7466613/ https://www.ncbi.nlm.nih.gov/pubmed/32784961 http://dx.doi.org/10.3390/nano10081567 |
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