Abstract
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 (ZT) are calculated with semiclassical Boltzmann transport equations (BTE). The results show that the n-type bilayer GeSe is a promising thermoelectric material.
Highlights
Academic Editor: Yaniv GelbsteinWith the decline of fossil fuel reserves and the increase in environmental pollution caused by energy consumption, the research activities related to the development of alternative technologies that can use renewable energy have increased significantly
The carrier concentration has the opposite effect on Seebeck coefficient and electrical conductivity: the decrease in carrier concentration increases the Seebeck coefficient, but it leads to a decrease in electrical conductivity, and vice versa
The monolayer GeSe and SnSe stripped from the bulk structures belong to the Pmn21 (No 31) space group
Summary
With the decline of fossil fuel reserves and the increase in environmental pollution caused by energy consumption, the research activities related to the development of alternative technologies that can use renewable energy have increased significantly. Toxic, high price, and low earth content are other factors restricting the development of thermoelectric materials [1,2] Layered material, such as thallium oxygen, bismuth oxygen selenide, and tin chalcogenide, show great promise in thermoelectric applications due to the intrinsic low lattice. Theoretical study has found that the 2D structure of group IV–VI compounds are thermodynamically stable with effectively low lattice thermal conductivity [25]. Stacking two 2D materials to construct a bilayer or van der Waals (vdW) heterostructure is an effective way to regulate the electronic structure and improve the thermoelectric properties of materials [30,31,32,33,34,35,36].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
