Semiconducting Chalcogenide Alloys Based on the (Ge, Sn, Pb) (S, Se, Te) Formula with Outstanding Properties: A First-Principles Calculation Study

Asadollah Bafekry; Masoud Shahrokhi; Aamir Shafique; Hamad R Jappor; Mohamed M Fadlallah; Catherine Stampfl; Mitra Ghergherehchi; Muhammad Mushtaq; Seyed Amir Hossein Feghhi; Daniela Gogova

doi:10.1021/acsomega.0c06024

Semiconducting Chalcogenide Alloys Based on the (Ge, Sn, Pb) (S, Se, Te) Formula with Outstanding Properties: A First-Principles Calculation Study

ACS Omega. 2021 Mar 30;6(14):9433-9441. doi: 10.1021/acsomega.0c06024. eCollection 2021 Apr 13.

Authors

Affiliations

¹ Department of Radiation Application, Shahid Beheshti University, 19839 69411 Tehran, Iran.
² Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
³ Department of Physics, Faculty of Science, University of Kurdistan, 66177-15175 Sanandaj, Iran.
⁴ Department of Physics, Lahore University of Management Sciences, 54792 Lahore, Pakistan.
⁵ Department of Physics, College of Education for Pure Sciences, University of Babylon, 964 Hilla, Iraq.
⁶ Department of Physics, Faculty of Science, Benha University, 13518 Benha, Egypt.
⁷ School of Physics, The University of Sydney, New South Wales 2006, Australia.
⁸ College of Electronic and Electrical Engineering, Sungkyunkwan University, 440-746 Suwon, Korea.
⁹ Department of Physics, Women University of Azad Jammu and Kashmir, 12500 Bagh, Pakistan.
¹⁰ Department of Physics, University of Oslo, P.O. Box 1048, Blindern, 0316 Oslo, Norway.

Abstract

Very recently, a new class of the multicationic and -anionic entropy-stabilized chalcogenide alloys based on the (Ge, Sn, Pb) (S, Se, Te) formula has been successfully fabricated and characterized experimentally [Zihao Deng et al., Chem. Mater. 32, 6070 (2020)]. Motivated by the recent experiment, herein, we perform density functional theory-based first-principles calculations in order to investigate the structural, mechanical, electronic, optical, and thermoelectric properties. The calculations of the cohesive energy and elasticity parameters indicate that the alloy is stable. Also, the mechanical study shows that the alloy has a brittle nature. The GeSnPbSSeTe alloy is a semiconductor with a direct band gap of 0.4 eV (0.3 eV using spin-orbit coupling effect). The optical analysis illustrates that the first peak of Im(ε) for the GeSnPbSSeTe alloy along all polarization directions is located in the visible range of the spectrum which renders it a promising material for applications in optical and electronic devices. Interestingly, we find an optically anisotropic character of this system which is highly desirable for the design of polarization-sensitive photodetectors. We have accurately predicted the thermoelectric coefficients and have calculated a large power factor value of 3.7 × 10¹¹ W m^-1 K^-2 s^-1 for p-type. The high p-type power factor is originated from the multiple valleys near the valence band maxima. The anisotropic results of the optical and transport properties are related to the specific tetragonal alloy unit cell.