Energetics and electronic structures of borders between MoS2 and WS2

We studied the energetics of two-dimensional in-plane heterostructures consisting of transition metal dichalcogenides, MoS2 and WS2, with respect to the border structure using density functional theory. A WS bond is energetically preferable at the border between MoS2 and WS2, so that the border tend to form WS bond as much as possible. We also found that the polarization at the zigzag border increases the total energy of the heterostructures. Competition between the bond formation energy and the polarization energy leads to chiral borders at which WS heterobonds are dominant. The border possesses type II band edge alignment with the band offsets of 0.16 and 0.28 eV for valence and conduction band edges, respectively. (C) 2019 The Japan Society of Applied Physics