A theoretical study on elastic, electronic, transport, optical and thermoelectric properties of Janus SnSO monolayer

Janus structures have superior physical properties due to their vertical asymmetric structure. Although oxygen is a chalcogen element (group VI), recent studies on Janus structures as well as monochalcogenides or dichalcogenides have usually focused on the 2H-phase of S, Se, and Te based compounds. In this study, we systematically investigate the structural, elastic, electronic, transport, optical, and thermoelectric properties of the 1T Janus SnSO monolayer using density functional theory. The Janus SnSO monolayer is found to be stable through phonon spectrum analysis and dynamics simulations. Obtained results demonstrate that SnSO monolayer possesses fully isotropic elastic properties and is more flexible than other two-dimensional materials. In the ground state, the SnSO monolayer is a semiconductor with a direct bandgap whose electronic properties can be easily controlled by strain engineering or the electric field. The electron mobility of the SnSO monolayer is found to be 216.460 cm2 V-1 s-1, which is favorable for applications in nanoscale electronics. The optical properties of the SnSO monolayer are accurately examined via the G_0W_0 plus the Bethe-Salpeter equation method. Our results reveal that SnSO has a wide absorption spectrum starting in the infrared and its maximum optical absorbance is up to 5.447 × 104 cm-1 in the near-ultraviolet region. Finally, we investigate the thermoelectric properties of the SnSO monolayer via the semiclassical Boltzmann transport theory. The relaxation time at room temperature is found to be 4.616 × 10-14 s. The doping level dependence of electronic transport coefficients of the SnSO monolayer is investigated in detail. © 2021 IOP Publishing Ltd.