1. Syntheses, structures, and optical properties of Ba4Ga4SnSe12 and Ba6Ga2SnSe11.
- Author
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Yin, Wenlong, Lin, Zuohong, Kang, Lei, Kang, Bin, Deng, Jianguo, Lin, Zheshuai, Yao, Jiyong, and Wu, Yicheng
- Subjects
SELENIDES ,CHALCOGENIDES ,SEMICONDUCTOR design ,CHEMICAL synthesis ,OPTICAL properties - Abstract
Two new quaternary selenides, namely Ba
4 Ga4 SnSe12 and Ba6 Ga2 SnSe11 , have been synthesized for the first time, representing the first two members in the A/M/Sn/Q (A = alkaline-earth metal; M = Al, Ga, In; Q = S, Se, Te) system. Ba4 Ga4 SnSe12 crystallizes in the non-centrosymmetric space group P4̅21 /c of the tetragonal system and has a three-dimensional structure. Its three-dimensional framework is built up from corner-sharing GaSe4 and SnSe4 tetrahedra with eight-coordinated Ba2+ cations residing in the cavities. Ba6 Ga2 SnSe11 crystallizes in a new structure type in the monoclinic centrosymmetric space group P21 /c. The structure of Ba6 Ga2 SnSe11 features a zero-dimensional structure containing totally isolated distorted SnSe4 tetrahedra and a discrete Ga2 Se7 unit with Ba2+ cations located between them. On the basis of the diffuse-reflectance spectra, the band gaps are 2.16 (2) eV and 1.99 (2) eV for Ba4 Ga4 SnSe12 and Ba6 Ga2 SnSe11 respectively. In addition, the electronic structure calculation of Ba4 Ga4 SnSe12 indicates that it is a direct-gap semiconductor with the band gap mainly determined by the [Ga4 SnSe12 ]8− anionic framework. [ABSTRACT FROM AUTHOR]- Published
- 2015
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