| Atomistic study of the alloying behavior of crystalline SnSe1-xSx | |||||
| 작성자 | 김** | 작성일 | 2018-08-30 | 조회수 | 87 |
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Journal Article published 2017 in Physical Chemistry Chemical Physics volume 19 issue 32 on pages 21648 to 21654
Authors: Trinh Thi Ly, Ganbat Duvjir, Taewon Min, Jinho Byun, Taehoon Kim, Mahmoud M. Saad, Nguyen Thi Minh Hai, Sunglae Cho, Jaekwang Lee, Jungdae Kim https://doi.org/10.1039/c7cp03481d Abstract Recently, layered chalcogenide alloys (LCAs) have been extensively investigated for use in various practical applications by selectively controlling the amount of foreign components. However, the alloying behavior of layered chalcogenides has been rarely explored at the atomistic level. Here, we study the microstructural evolution of SnSe1?xSx alloys on the atomic scale by combining scanning tunneling microscopy (STM) measurements with first-principles density functional theory (DFT) calculations. STM topographic images suggest that S atoms substituted in SnSe1?xSx are not randomly distributed, but tend to form local SnS clusters. The degree of S atom alloying was quantitatively estimated to be about 60% from STM images, indicating that homo-atoms (S?S) are a preferred arrangement over hetero-atoms (S?Se). Our DFT calculations further confirmed that the mixing energy of random SnSe1?xSx alloys showed positive behavior over the whole S composition range considered. This result suggests that SnSe1?xSx has a tendency toward local phase segregation into SnSe and SnS rather than random alloys. We expect our atomistic study on the alloying behavior to provide important insight for fabricating optimal SnSe1?xSx alloys with high thermoelectric properties. |
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