Learning Forum

[Faiaad39]

Hi, 

                                                                        

I am trying to build a 3D spherical stack solar cell structure in Ansys Lumerical FDTD & CHARGE.

I have modeled the structure in CHARGE Solver using the given structural model.

I have tried to simulate the structure in 3D in CHARGE Solver, but it is stuck in "Meshing" and showing "Meshing Status - "Tesselating"

So, I tried running in 2D simulation in CHARGE Solver (Taking 2D Y normal), but it is showing the error message

"Refinement limit exceeded for auto-refinement. The mesh is valid but may not be adequately refined.

 Could not locate matching boundary". 

I have set all the necessary boundary conditions and imported optical generation profiles from FDTD to CHARGE.

[P.S: The structure was simulated smoothly while modeling in planar form]

 

Can you please help me to figure out why it is showing such error messages?

[Guilin Sun]

It is common when the curved surface is connected with a planar surface, as the corner needs much finer triangles to mesh it. 

The property “max refine steps” in "mesh" tab determines how many iterations are allowed during the mesh refinement process. Sometimes, the default number is not large enough for the refinement to finish within the allowed number of iterations. In such a case, the refining will stop before the mesh becomes fine enough to capture the variation in the doping or optical generation profile. The solver then generates a warning message saying that the mesh is not refined enough.
The easiest way to solve this problem is to increase the value of “max refine steps” so that the solver gets the opportunity to properly refine the mesh and the warning should go away. You can learn about the different parameters that CHARGE uses in calculating the mesh from https://optics.ansys.com/hc/en-us/articles/360034918633-CHARGE-solver-Simulation-object

Since 2D has this issue, 3D will be more challenge. You could try to ass small edged ring around this interface to replease the strict meshing requirement.

you can imaging in real device it will not be the perfect geometry. You may simulate half of the structure depending on where the contacts are located.