Regarding the parameter sweep for the 2D graphene file, it looks like no parameters have been set up to sweep and no results are set up to be collected. These settings have to be chosen by the user before running the sweep, and you can choose the settings to sweep and results to collect by editing the sweep. There are step-by-step instructions showing how to edit the sweep and set up the values to sweep and results to collect here:
For question 2, you can add a mesh override region from the “Simulation” menu in the main toolbar.
When you edit the mesh override region object you can set the x position and span of the mesh override to match the position of the graphene rectangle under the “Geometry” tab of the edit window. In the “General” tab you can type in the value for the “dx” setting to specify the mesh step size you want to use in the x-direction. Ideally at least 2 mesh cells should be used over the thickness of the layer in order to be able to resolve the thickness of the layer. You can do convergence testing by first using 2 mesh cells over the thickness, and increasing to 3, 4, 5, etc. mesh cells until the reflection and transmission results no longer change when you increase the number of mesh cells used over the layer. This way you can make sure that the mesh is fine enough for accurate results.
For question 3, representing the graphene by using the 2D rectangle instead of 3D rectangle is preferred because you don’t need to use as fine of a mesh around the graphene in order to get an accurate result. Since a coarser mesh can be used for the 2D rectangle, the simulation can be run faster and requires less memory to run.
If you need more details please let me know!