Simulating realistic heterostructures of group-III monochalcogenides: commensurability versus incommensurability and the role of the dielectric screening
Juliana Morbec, University of Duisburg-Essen, Duisburg, GermanyAltaf Rahman, Department of Physics, Quaid-i-Azam University, Islamabad, PakistanGul Rahman, Department of Physics, Quaid-i-Azam University, Islamabad, PakistanPeter Kratzer, Faculty of Physics, University of Duisburg-Essen, Duisburg, Germany
The two-dimensional (2D) group-III monochalcogenides GaS, GaSe, InS, and InSe are considered to be promising materials for applications in optoelectronics and solar energy conversion. The band structures of these systems are complex, and their band gaps and band edge positions are very sensitive to strain and dependent on the number of layers in 2D stacks. Here we present a theoretical investigation on how the valence and conduction bands of GaS, GaSe, InS and InSe are affected by stacking in homobilayers and heterostructures. In order to simulate realistic heterostructures, we consider the cases of commensurate and incommensurate stacking and we compute the cost of having commensurate structures. We also investigate the effect of strain on the band gaps and band edge positions of the monolayer systems and we use these results to demonstrate the consequences of different stacking for the band alignment of the GaS/GaSe and GaSe/InS heterostructures. Finally, we examine the changes in the electronic properties of these stacked systems due to the dielectric screening.