Density functional theory: The structural, electronic, optical, mechanical, and vibrational properties of bulk and Te-doped SnSe2

This work performs a computational prediction on SnSe2 and Te-doped bilayer material. Doping the Te element onto SnSe2 can lead to a decrease in bandgap E-g energy (from 1.95 eV to 0.94 eV) and cause a drop in both conduction band (CB) and valence band (VB), apart from the valence band maximum (VBM). This may lead to an increase in electrical conductivity. The decrease in g(2) parameter may result in an impact on electronic effective mass and transport properties when the SnSe2 bilayer is doped with Te. A redshift observed on both the optical absorption and the dielectric constant plots may suggest that a tensile force could be possibly induced when we dope the SnSe2 compound. The identical elastic constants of C-14 and C-65 evaluated could describe the nature of the close-packed hexagonal bilayer. Finally, the ductility slightly increases when we mix the Te element onto the SnSe2 alloy. It is also worth noting that both SnSe2 and Te-doped are dynamically stable, according to the phonon dispersion.