Observation of interacting polaronic gas behavior in Ta-doped TiO2 thin films via terahertz time-domain spectroscopy
Transparent conductive oxides (TCOs)—materials that have the twin desirable features of high optical transmission and electrical conductivity—play an increasingly significant role in the fields of photovoltaics and information technology. As an excellent TCO, Ta-doped anatase TiO2 shows great promis...
| Main Authors: | , , , , , , , , |
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| Format: | Journal Article |
| Language: | English |
| Published: |
2021
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| Online Access: | https://hdl.handle.net/10356/148241 |
| _version_ | 1811686060992757760 |
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| author | Cheng, Liang Sarkar, Tarapada Lourembam, James Tutchton, Roxanne Motapathula, M. Zhao, Daming Zhu, Jian-Xin Venkatesan, Thirumalai Chia, Elbert E. M. |
| author2 | School of Physical and Mathematical Sciences |
| author_facet | School of Physical and Mathematical Sciences Cheng, Liang Sarkar, Tarapada Lourembam, James Tutchton, Roxanne Motapathula, M. Zhao, Daming Zhu, Jian-Xin Venkatesan, Thirumalai Chia, Elbert E. M. |
| author_sort | Cheng, Liang |
| collection | NTU |
| description | Transparent conductive oxides (TCOs)—materials that have the twin desirable features of high optical transmission and electrical conductivity—play an increasingly significant role in the fields of photovoltaics and information technology. As an excellent TCO, Ta-doped anatase TiO2 shows great promise for a wide range of applications. Here, terahertz time-domain spectroscopy is used to study the complex optical conductivity r~ðxÞ of the TCO—heavily Ta-doped TiO2 thin films with different Ta-doping concentrations, in the frequency range of 0.3–2.7 THz and the temperature range of 10–300 K. Fitting the complex optical conductivity to a Drude-like behavior allows us to extract the temperature dependence of the effective mass, which suggests the existence of many-body large polarons. Moreover, the carrier scattering rate of Ta-doped TiO2 with different carrier concentrations agrees with the interacting polaron gas theory. Our results suggest that with increasing electron density in TiO2, the interaction between polarons is larger and electron–phonon coupling is smaller, which is beneficial for achieving high mobility and conductivity in TiO2. |
| first_indexed | 2024-10-01T04:54:25Z |
| format | Journal Article |
| id | ntu-10356/148241 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T04:54:25Z |
| publishDate | 2021 |
| record_format | dspace |
| spelling | ntu-10356/1482412023-02-28T20:00:43Z Observation of interacting polaronic gas behavior in Ta-doped TiO2 thin films via terahertz time-domain spectroscopy Cheng, Liang Sarkar, Tarapada Lourembam, James Tutchton, Roxanne Motapathula, M. Zhao, Daming Zhu, Jian-Xin Venkatesan, Thirumalai Chia, Elbert E. M. School of Physical and Mathematical Sciences School of Materials Science and Engineering Science::Physics Interacting Polaronic Gas Terahertz Time-domain Spectroscopy Transparent conductive oxides (TCOs)—materials that have the twin desirable features of high optical transmission and electrical conductivity—play an increasingly significant role in the fields of photovoltaics and information technology. As an excellent TCO, Ta-doped anatase TiO2 shows great promise for a wide range of applications. Here, terahertz time-domain spectroscopy is used to study the complex optical conductivity r~ðxÞ of the TCO—heavily Ta-doped TiO2 thin films with different Ta-doping concentrations, in the frequency range of 0.3–2.7 THz and the temperature range of 10–300 K. Fitting the complex optical conductivity to a Drude-like behavior allows us to extract the temperature dependence of the effective mass, which suggests the existence of many-body large polarons. Moreover, the carrier scattering rate of Ta-doped TiO2 with different carrier concentrations agrees with the interacting polaron gas theory. Our results suggest that with increasing electron density in TiO2, the interaction between polarons is larger and electron–phonon coupling is smaller, which is beneficial for achieving high mobility and conductivity in TiO2. Ministry of Education (MOE) National Research Foundation (NRF) Accepted version We thank the Singapore Ministry of Education (MOE) Tier 1 (No. MOE2018-T1-1-097) and Tier 2 (No. MOE2019-T2-1-097) grants, NUSNNI-NanoCore at the National University of Singapore (NUS) and the Singapore National Research Foundation (NRF) under the Competitive Research Programs (CRP No. NRF-CRP15-2015-01), NUS cross-faculty grant, and FRC (ARF Grant No. R-144-000-278- 112) for financial support. The work at Los Alamos was carried out under the auspices of the U.S. Department of Energy (DOE) National Nuclear Security Administration under Contract No. 89233218CNA000001 and was supported by the U.S. DOE BES under the No. LANL E3B5 and LANL LDRD Program. This research used resources of NERSC (DOE Contract No. DE-AC02-05CH11231) and the Institutional Computing Program at LANL with the support of the Center for Integrated Nanotechnologies, a DOE BES user facility. The x-ray diffraction work was performed at the Facility for Analysis, Characterization, Testing and Simulation (FACTS), Nanyang Technological University, Singapore. 2021-06-16T08:00:28Z 2021-06-16T08:00:28Z 2020 Journal Article Cheng, L., Sarkar, T., Lourembam, J., Tutchton, R., Motapathula, M., Zhao, D., Zhu, J., Venkatesan, T. & Chia, E. E. M. (2020). Observation of interacting polaronic gas behavior in Ta-doped TiO2 thin films via terahertz time-domain spectroscopy. Applied Physics Letters, 117(26), 261902-1-261902-6. https://dx.doi.org/10.1063/5.0022775 1077-3118 https://hdl.handle.net/10356/148241 10.1063/5.0022775 26 117 261902-1 261902-6 en MOE2018-T1-1-097 MOE2019-T2-1-097 NRF-CRP15-2015-01 R-144-000-278-112 89233218CNA000001 LANL E3B5 DE-AC02-05CH11231 Applied Physics Letters © 2020 The Author(s). Published by AIP. This paper was published in Applied Physics Letters and is made available with permission of The Author(s). Published by AIP. application/pdf |
| spellingShingle | Science::Physics Interacting Polaronic Gas Terahertz Time-domain Spectroscopy Cheng, Liang Sarkar, Tarapada Lourembam, James Tutchton, Roxanne Motapathula, M. Zhao, Daming Zhu, Jian-Xin Venkatesan, Thirumalai Chia, Elbert E. M. Observation of interacting polaronic gas behavior in Ta-doped TiO2 thin films via terahertz time-domain spectroscopy |
| title | Observation of interacting polaronic gas behavior in Ta-doped TiO2 thin films via terahertz time-domain spectroscopy |
| title_full | Observation of interacting polaronic gas behavior in Ta-doped TiO2 thin films via terahertz time-domain spectroscopy |
| title_fullStr | Observation of interacting polaronic gas behavior in Ta-doped TiO2 thin films via terahertz time-domain spectroscopy |
| title_full_unstemmed | Observation of interacting polaronic gas behavior in Ta-doped TiO2 thin films via terahertz time-domain spectroscopy |
| title_short | Observation of interacting polaronic gas behavior in Ta-doped TiO2 thin films via terahertz time-domain spectroscopy |
| title_sort | observation of interacting polaronic gas behavior in ta doped tio2 thin films via terahertz time domain spectroscopy |
| topic | Science::Physics Interacting Polaronic Gas Terahertz Time-domain Spectroscopy |
| url | https://hdl.handle.net/10356/148241 |
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