Two-dimensional materials have attracted considerable interest due to their exceptional and unique properties, which enable a wide range of applications in the fields of optoelectronics, thermoelectricity, and photocatalysis. In this work, we systematically study the Janus monolayer SbTeCl in its 1T and 2H structural phases, focusing on the effects of biaxial strain and an external electric field. Calculations were performed using ab initio methods based on density functional theory (DFT). Analyses of phonon dispersion and elastic constants confirm the dynamical and mechanical stability of the 1T-SbTeCl monolayer, indicating its potential experimental feasibility, whereas the 2H-SbTeCl phase appears to be dynamically unstable. Electronic calculations reveal that both phases are indirect semiconductors, with band gaps of 1 . 56 eV ( 2 . 13 eV ) for 1T-SbTeCl and 1 . 66 eV ( 2 . 32 eV ) for 2H-SbTeCl, obtained using GGA-PBE (HSE06) functionals. Furthermore, SbTeCl monolayer exhibits a high optical absorption coefficient in the visible and ultraviolet ranges, suggesting that it is suitable for high-efficiency optoelectronic applications. Our results demonstrate that biaxial strain applied to the SbTeCl monolayer in both phases (1T and 2H) can effectively tune the electronic and optical properties, while the impact of the external electric field remains relatively limited. The thermoelectric performance evaluation shows a figure of merit Z T reaching 3.36 for 1T-SbTeCl and 4.48 for 2H-SbTeCl at 800 K in the p - and n -type regions, respectively. These findings highlight SbTeCl as a highly promising candidate for next-generation optoelectronic and thermoelectric devices.
Adadi et al. (Thu,) studied this question.