Theoretical design of Janus-In2STe/InSe lateral heterostructure: A DFT investigation

Recent great advances in the study of heterostructure engineering have motivated us to study the Janus-In2STe/ InSe lateral heterostructure (LHS). By using the density functional theory (DFT) calculation, the stability, electronic, and optical properties of Janus-In2STe/InSe LHS are systematically investigated. The calculated results indicate that the Janus-In2STe/InSe LHS is theoretical stable because of small lattice mismatch and low heats of formation. It is also found that the Janus-In2STe/InSe LHS always presents a direct band gap semiconducting character with type-I band alignment regardless of the heterostructure width. The band gaps reduce slowly with increasing component units of the heterostructure. Particularly, the significant charge transfer from Janus In2STe to InSe layer can be found, resulting in a reasonable and moderate work function of the LHS, whose value is between Janus-In2STe and InSe. In addition, the Janus-In2STe/InSe LHS also exhibit a high optical absorption coefficient (~8 x 105 cm-1) from visible light zone to ultraviolet light zone. The present calculated results suggest that the Janus-In2STe/InSe LHS can be a good candidate material for optoelectronic devices.