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In Situ Raman Investigation of TiO(2) Nanotube Array-Based Ultraviolet Photodetectors: Effects of Nanotube Length
TiO(2) nanotube arrays (TNAs) with tube lengths of 4, 6, and 7 μm were prepared via two-step anodization. Thereafter, ultraviolet (UV) photodetectors (PDs) with Au/TiO(2)/Au structures were prepared using these TNAs with different tube lengths. The effects of TNA length and device area on the perfor...
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/PMC7221791/ https://www.ncbi.nlm.nih.gov/pubmed/32316530 http://dx.doi.org/10.3390/molecules25081854 |
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author | Ren, Yanyu Shi, Xiumin Xia, Pengcheng Li, Shuang Lv, Mingyang Wang, Yunxin Mao, Zhu |
author_facet | Ren, Yanyu Shi, Xiumin Xia, Pengcheng Li, Shuang Lv, Mingyang Wang, Yunxin Mao, Zhu |
author_sort | Ren, Yanyu |
collection | PubMed |
description | TiO(2) nanotube arrays (TNAs) with tube lengths of 4, 6, and 7 μm were prepared via two-step anodization. Thereafter, ultraviolet (UV) photodetectors (PDs) with Au/TiO(2)/Au structures were prepared using these TNAs with different tube lengths. The effects of TNA length and device area on the performance of the device were investigated using in situ Raman spectroscopy. The maximum laser/dark current ratio was achieved by using a TNA with a size of 1 × 1 cm(2) and a length of 7 μm, under a 532 nm laser. In addition, when the device was irradiated with a higher energy laser (325 nm), the UV Raman spectrum was found to be more sensitive than the visible Raman spectrum. At 325 nm, the laser/dark current ratio was nearly 24 times higher than that under a 532 nm laser. Six phonon modes of anatase TNAs were observed, at 144, 199, 395, 514, and 635 cm(−1), which were assigned to the E(g(1)), E(g(2)), B(1g(1)), A(1g)/B(1g(2)), and E(g(3)) modes, respectively. The strong low-frequency band at 144 cm(−1) was caused by the O-Ti-O bending vibration and is a characteristic band of anatase. The results show that the performance of TNA-based PDs is length-dependent. Surface-enhanced Raman scattering signals of 4-mercaptobenzoic acid (4-MBA) molecules were also observed on the TNA surface. This result indicates that the length-dependent performance may be derived from an increase in the specific surface area of the TNA. In addition, the strong absorption of UV light by the TNAs caused a blueshift of the E(g(1)) mode. |
format | Online Article Text |
id | pubmed-7221791 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-72217912020-05-21 In Situ Raman Investigation of TiO(2) Nanotube Array-Based Ultraviolet Photodetectors: Effects of Nanotube Length Ren, Yanyu Shi, Xiumin Xia, Pengcheng Li, Shuang Lv, Mingyang Wang, Yunxin Mao, Zhu Molecules Article TiO(2) nanotube arrays (TNAs) with tube lengths of 4, 6, and 7 μm were prepared via two-step anodization. Thereafter, ultraviolet (UV) photodetectors (PDs) with Au/TiO(2)/Au structures were prepared using these TNAs with different tube lengths. The effects of TNA length and device area on the performance of the device were investigated using in situ Raman spectroscopy. The maximum laser/dark current ratio was achieved by using a TNA with a size of 1 × 1 cm(2) and a length of 7 μm, under a 532 nm laser. In addition, when the device was irradiated with a higher energy laser (325 nm), the UV Raman spectrum was found to be more sensitive than the visible Raman spectrum. At 325 nm, the laser/dark current ratio was nearly 24 times higher than that under a 532 nm laser. Six phonon modes of anatase TNAs were observed, at 144, 199, 395, 514, and 635 cm(−1), which were assigned to the E(g(1)), E(g(2)), B(1g(1)), A(1g)/B(1g(2)), and E(g(3)) modes, respectively. The strong low-frequency band at 144 cm(−1) was caused by the O-Ti-O bending vibration and is a characteristic band of anatase. The results show that the performance of TNA-based PDs is length-dependent. Surface-enhanced Raman scattering signals of 4-mercaptobenzoic acid (4-MBA) molecules were also observed on the TNA surface. This result indicates that the length-dependent performance may be derived from an increase in the specific surface area of the TNA. In addition, the strong absorption of UV light by the TNAs caused a blueshift of the E(g(1)) mode. MDPI 2020-04-17 /pmc/articles/PMC7221791/ /pubmed/32316530 http://dx.doi.org/10.3390/molecules25081854 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 Ren, Yanyu Shi, Xiumin Xia, Pengcheng Li, Shuang Lv, Mingyang Wang, Yunxin Mao, Zhu In Situ Raman Investigation of TiO(2) Nanotube Array-Based Ultraviolet Photodetectors: Effects of Nanotube Length |
title | In Situ Raman Investigation of TiO(2) Nanotube Array-Based Ultraviolet Photodetectors: Effects of Nanotube Length |
title_full | In Situ Raman Investigation of TiO(2) Nanotube Array-Based Ultraviolet Photodetectors: Effects of Nanotube Length |
title_fullStr | In Situ Raman Investigation of TiO(2) Nanotube Array-Based Ultraviolet Photodetectors: Effects of Nanotube Length |
title_full_unstemmed | In Situ Raman Investigation of TiO(2) Nanotube Array-Based Ultraviolet Photodetectors: Effects of Nanotube Length |
title_short | In Situ Raman Investigation of TiO(2) Nanotube Array-Based Ultraviolet Photodetectors: Effects of Nanotube Length |
title_sort | in situ raman investigation of tio(2) nanotube array-based ultraviolet photodetectors: effects of nanotube length |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7221791/ https://www.ncbi.nlm.nih.gov/pubmed/32316530 http://dx.doi.org/10.3390/molecules25081854 |
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