Se/Sn flux ratio effects on epitaxial SnSe thin films; crystallinity & domain rotation
| Autor: | Cao Khang Nguyen, Anh Tuan Pham, Anh Tuan Duong, Van Quang Nguyen, Rakwon Kang, Van Thiet Duong, Thang Bach Phan, Jungdae Kim, Sunglae Cho, Thi Huong Nguyen, Van Tam Tran |
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| Rok vydání: | 2020 |
| Předmět: |
Materials science
Mechanical Engineering Metals and Alloys Analytical chemistry Flux 02 engineering and technology Crystal structure Substrate (electronics) 010402 general chemistry 021001 nanoscience & nanotechnology Epitaxy 01 natural sciences 0104 chemical sciences Crystallinity Mechanics of Materials Thermoelectric effect Materials Chemistry Orthorhombic crystal system Thin film 0210 nano-technology |
| Zdroj: | Journal of Alloys and Compounds. 840:155680 |
| ISSN: | 0925-8388 |
| DOI: | 10.1016/j.jallcom.2020.155680 |
| Popis: | We report on the effects of Se/Sn flux ratio to the growth and thermoelectric properties of SnSe thin films on MgO (100) substrate. All films were epitaxially grown at 300 °C with various Se/Sn flux ratios of 0.8, 0.9, 1, 3, 5, and 7. The crystal structure of the obtained SnSe thin films was orthorhombic (Pnma space group) with a-axis (h00) orientation. XRD Φ-scan studies showed an existence of orthorhombic domains, whose rotation can be modulated by the Se/Sn flux ratio. A structure consisting of 0° and 90° rotated domains was observed in all samples, while additional 45° rotated domains were simultaneously observed in the samples with higher Se/Sn ratio of 5 and 7. Especially, 135° rotated domains were observed in sample Se/Sn = 7. Interestingly, the best crystalline film was obtained at the Se/Sn = 1. We found that Seebeck coefficients were positive at room temperature, decreased with temperature and became negative for the sample Se/Sn = 1, indicating bipolar transport in the samples. A maximum PF value of 3.74 μWc m −1 K −2 was obtained at 550 K for sample Se/Sn = 0.8 . |
| Databáze: | OpenAIRE |
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