Atomistic study of the alloying behavior of crystalline SnSe1−xSx. Issue 32 (2nd August 2017)

• Record Type: Journal Article
• Authors: Ly, Trinh Thi; Duvjir, Ganbat; Min, Taewon; Byun, Jinho; Kim, Taehoon; Saad, Mahmoud M.; Hai, Nguyen Thi Minh; Cho, Sunglae; Lee, Jaekwang; Kim, Jungdae
• Is Part Of: Physical chemistry chemical physics. Volume 19:Issue 32(2017)
• Page Start: 21648
• Page End: 21654
• Publication Date: 2017-08-02
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c7cp03481d
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : The alloying behavior of crystalline SnSe1− x S x was investigated at the atomic level by combining STM experiments and DFT calculations. 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− x S x 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− x S x 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− x S x alloys showed positive behavior over the whole S composition range considered. This result suggests that SnSe1− x S x 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− x S x alloys with high thermoelectric properties.