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Group 14 elements in the Cmcm phase with a direct band structure for photoelectric application

MetadataDetails
Publication Date2022-11-18
JournalPhysica Scripta
AuthorsQingyang Fan, Yichao Sun, Yingbo Zhao, Yanxing Song, Sining Yun
InstitutionsXi’an University of Architecture and Technology, Xidian University
Citations22

Abstract This work presents two novel group 14 element allotropes, o C24 Si 24 and o C24 Ge 24 , and the physical properties of o C24 C 24 , o C24 Si 24 , and o C24 Ge 24 are studied in detail by means of first-principles calculations. The mechanical stability, dynamic stability, and thermodynamic stability of o C24 Si 24 and o C24 Ge 24 are proven by the elastic parameters, phonon spectrum, and relative enthalpy, respectively. According to the B / G value, all o C24 C 24 , o C24 Si 24 , and o C24 Ge 24 are brittle materials. By analysing the directional dependence of Young’s modulus, it is clear that o C24 Si 24 possesses the largest mechanical anisotropy. From the electronic properties, it can be concluded that o C24 Si 24 is a semiconductor material with a direct band gap of 1.047 eV, which suggests that o C24 Si 24 may be suitable to make solar cells. More importantly, the light absorption ability of o C24 Si 24 is stronger than that of diamond Si in the visible light region. In addition, the Îș min of o C24 Si 24 and o C24 Ge 24 have better thermal conductivity, indicating that o C24 Si 24 and o C24 Ge 24 have great application potential in solar cells, optoelectronic devices and other microelectronic devices.