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Native point defects and low p-doping efficiency in Mg2(Si,Sn) solid solutions: A hybrid-density functional study

Year: 2020
Type: article
Abstract: We perform hybrid-density functional calculations to investigate the charged defect formation energy of native point defects in Mg2Si, Mg2Sn, and their solid solutions. The band gap correction by hybrid-density functional is found to be critical to determine the charged defect density in these materials. For Mg2Si, Mg interstitials are dominant and provide unintentional n-type conductivity. Additionally, as the Mg vacancies can dominate in Mg-poor Mg2Sn, p-type conductivity is possible for Mg2Sn. However, the existence of low formation energy defects such as MgSn1+ and IMg2+ in Mg2Sn and their diffusion can cause severe charge compensation of hole carriers resulting in low p-type doping efficiency and thermal degradation. Our results indicate that, in addition to the extrinsic doping strategy, alloying of Mg2Sn with Mg2Si under Mg-poor conditions would be necessary to enhance the p-type conductivity with less charge compensation.
DOI: 10.1016/j.jallcom.2020.157145
Authors: Byungki Ryu, Eun-Ae Choi, Sungjin Park, Jaywan Chung, Johannes de Boor, Pawel Ziolkowski, Eckhard Müller, SuDong Park
Language: English
Open Access status: hybrid
Estimated APC paid: $3,050
Funders: Deutsche Forschungsgemeinschaft, Ministry of Trade, Industry and Energy, Korea Electrotechnology Research Institute, National Research Council of Science and Technology, Ministry of Science and ICT, South Korea, Korea Institute of Energy Technology Evaluation and Planning
Awards: G1387828278, G2009101430, G2796408166, Entschlüsselung des Zusammenspiels zwischen Defekten, Dotierelement und thermoelektrischen Eigenschaften in pdotiertem Mg2X (X=Si, Ge, Sn), G485685651, G6588402948, G7884461437
OpenAlex ID: W3010700985
FWCI: 1.401
Cites: 42
Cited by: 30
Related to: 10