Band Engineering of Monolayer WS₂ by Sumanene Columns

High Resolution Image Download MS PowerPoint Slide Electronic structures of monolayer WS 2 adsorbing sumanene (C 21 H 12 ) columns are investigated in terms of the molecular conformation and the column length using density functional theory. Our calculations indicated that the electronic structures of WS 2 strongly depend on the molecular conformation of sumanene and the column length: The valence and conduction band edges of WS 2 monotonically shift upward with increasing column length when the columns are adsorbed in the bowl-head arrangement to WS 2 . The band edges monotonically shift downward with increasing column length when the columns are adsorbed in a bowl-edge arrangement. The upward and downward shifts of the band edges are ascribed to the dipole moment of the sumanene columns, which is proportional to the column length. We further investigated the electronic structure of a superlattice comprising WS 2 adsorbing sumanene column arrays with bowl-head and bowl-edge arrangements. WS 2 covered by sumanene columns is a semiconductor with a staggered band edge alignment depending on the column orientations.