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| Main Authors: | , , , , , , |
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| Format: | Preprint |
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2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2401.07953 |
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| _version_ | 1866910298424737792 |
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| author | Meng, Jun Abbasi, Mehrdad Dong, Yutao Carlosa, Corey Wang, Xudong Hwang, Jinwoo Morgan, Dane |
| author_facet | Meng, Jun Abbasi, Mehrdad Dong, Yutao Carlosa, Corey Wang, Xudong Hwang, Jinwoo Morgan, Dane |
| contents | Amorphous titanium dioxide TiO2 (a-TiO2) has been widely studied, particularly as a protective coating layer on semiconductors to prevent corrosion and promote electron-hole conduction in photoelectrochemical reactions. The stability and longevity of a-TiO2 is strongly affected by the thickness and structural heterogeneity, implying that understanding the structure properties of a-TiO2 is crucial for improving the performance. This study characterized the structural and electronic properties of a-TiO2 thin films (~17nm) grown on Si by Atomic Layer Deposition (ALD). Fluctuation spectra V(k) and angular correlation functions were determined with 4-dimensional scanning transmission electron microscopy (4D-STEM), which revealed the distinctive medium-range ordering in the a-TiO2 film. A realistic atomic model of a-TiO2 was established guided by the medium-range ordering and the previously reported short-range ordering of a-TiO2 film, as well as the interatomic potential. The structure was optimized by the StructOpt code using a genetic algorithm that simultaneously minimizes energy and maximizes match to experimental short- and medium-range ordering. The StructOpt a-TiO2 model presents an improved agreements with the medium-range ordering and the k-space location of the dominant 2-fold angular correlations compared with a traditional melt-quenched model. The electronic structure of the StructOpt a-TiO2 model was studied by ab initio calculation and compared to the crystalline phases and experimental results. This work uncovered the medium-range ordering in a-TiO2 thin film and provided a realistic a-TiO2 structure model for further investigation of structure-property relationships and materials design. In addition, the improved multi-objective optimization package StructOpt was provided for structure determination of complex materials guided by experiments and simulations. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2401_07953 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Experimentally informed structure optimization of amorphous TiO2 films grown by atomic layer deposition Meng, Jun Abbasi, Mehrdad Dong, Yutao Carlosa, Corey Wang, Xudong Hwang, Jinwoo Morgan, Dane Materials Science Amorphous titanium dioxide TiO2 (a-TiO2) has been widely studied, particularly as a protective coating layer on semiconductors to prevent corrosion and promote electron-hole conduction in photoelectrochemical reactions. The stability and longevity of a-TiO2 is strongly affected by the thickness and structural heterogeneity, implying that understanding the structure properties of a-TiO2 is crucial for improving the performance. This study characterized the structural and electronic properties of a-TiO2 thin films (~17nm) grown on Si by Atomic Layer Deposition (ALD). Fluctuation spectra V(k) and angular correlation functions were determined with 4-dimensional scanning transmission electron microscopy (4D-STEM), which revealed the distinctive medium-range ordering in the a-TiO2 film. A realistic atomic model of a-TiO2 was established guided by the medium-range ordering and the previously reported short-range ordering of a-TiO2 film, as well as the interatomic potential. The structure was optimized by the StructOpt code using a genetic algorithm that simultaneously minimizes energy and maximizes match to experimental short- and medium-range ordering. The StructOpt a-TiO2 model presents an improved agreements with the medium-range ordering and the k-space location of the dominant 2-fold angular correlations compared with a traditional melt-quenched model. The electronic structure of the StructOpt a-TiO2 model was studied by ab initio calculation and compared to the crystalline phases and experimental results. This work uncovered the medium-range ordering in a-TiO2 thin film and provided a realistic a-TiO2 structure model for further investigation of structure-property relationships and materials design. In addition, the improved multi-objective optimization package StructOpt was provided for structure determination of complex materials guided by experiments and simulations. |
| title | Experimentally informed structure optimization of amorphous TiO2 films grown by atomic layer deposition |
| topic | Materials Science |
| url | https://arxiv.org/abs/2401.07953 |