Band gap engineering of tungsten disulfide (WS2) nanoribbon by applying elastic strain and electric field

Transition metal dichalcogenides (TMDs) have generated a lot of interest recently. They can form nanoribbons like graphene and such nanoribbons have versatile electronic structures and can be metallic or semiconducting by changing the edges of the ribbon. In this paper we investigate effects on band structure of WS2 nanoribbons (armchair and zigzag) by applying uniaxial strain and external electric field perpendicular to the layers studied by DFT using siesta. The band gap of WS2 armchair nanoribbon continuously decreases with increasing external electric field, eventually a transition from semiconductor to metal is observed.