Exceptional Thermoelectric Properties of Bilayer GeSe: First Principles Calculation

• Published in: Materials Vol. 15; no. 3; p. 971
• Main Authors: Fan, Qiang, Zhang, Weibin, Qing, Haiyin, Yang, Jianhui
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 27-01-2022; MDPI
• Subjects: Approximation; Bilayers; Boltzmann transport equation; Dynamic stability; Electrical resistivity; electronic structure; Energy; Energy gap; Figure of merit; First principles; GeSe; Heat conductivity; heterostructure; Heterostructures; Mathematical analysis; Phonons; Power factor; Seebeck effect; SnSe; Structural stability; Thermal conductivity; Thermoelectric materials; thermoelectric properties; Thermoelectricity; Transport theory; GeSe; SnSe; heterostructure; thermoelectric properties; electronic structure
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma15030971

The geometry structures, vibrational, electronic, and thermoelectric properties of bilayer GeSe, bilayer SnSe, and van der Waals (vdW) heterostructure GeSe/SnSe are investigated by combining the first-principles calculations and semiclassical Boltzmann transport theory. The dynamical stability of the considered structures are discussed with phonon dispersion. The phonon spectra indicate that the bilayer SnSe is a dynamically unstable structure, while the bilayer GeSe and vdW heterostructure GeSe/SnSe are stable. Then, the electronic structures for the bilayer GeSe and vdW heterostructure GeSe/SnSe are calculated with HSE06 functional. The results of electronic structures show that the bilayer GeSe and vdW heterostructure GeSe/SnSe are indirect band gap semiconductors with band gaps of 1.23 eV and 1.07 eV, respectively. The thermoelectric properties, including electrical conductivity, thermal conductivity, Seebeck coefficient, power factor, and figure of merit (
) are calculated with semiclassical Boltzmann transport equations (BTE). The results show that the
-type bilayer GeSe is a promising thermoelectric material.