Up to now, I used the 2D surface conductivity model of graphene extensively in my simulations and I am pretty comfortable with it.
Then, I wanted to try MoS2 instead of graphene, but realized that there is no 2D model of MoS2 documented by Lumerical. So, I picked the permittivity values from this post, 2d material reflection, and then converted the permittivity to conductivity by using https://kb.lumerical.com/en/materials_create-2d-conductivity.html.
I specified the MoS2 layer thickness as 0.615 nm. After that I simulated the monolayer MoS2 alone and its reflection,transmission, absorption spectrums with the 2D and 3D models revealed identical. So, I continued all of my simulations with the 2D model of MoS2. When I tried to switch back to 3D model of MoS2 for confirmation, 1.5 hours of max.time remaining became 200 hours (thickness/6 mesh override on MoS2).
Now, I need to put MoS2 on top of graphene. I would strongly prefer using the 2D models as they reduce the simulation times immensely. I tried to put graphene and MoS2 to the same vertical location (similar to putting 2D rectangles at the boundaries of objects) and see the absorption but it was identical to that of MoS2.
So, my question is, is there any way to efficiently put MoS2 on top of graphene?