how to reduce the Fabry–Pérot interference?

- July 3, 2024 at 2:16 am
  
  handon
  Subscriber
  
  Hello, I found that light interference usually happens in the simulation of finite-thick solar cells, causing oscillation in the reflectance graph. This is especially severe when they are coated with semi-transparent materials and structures.
  How can I reduce the Fabry–Pérot interference?
  The solar cell structure is like below:
  -      Si substrate thickness = 150 μm
  -      The SiNx layer is coated for the front and rear sides.
  -      The MD600 (a kind of polymer material) hyperbola structure is formed for the front and rear sides.
- July 4, 2024 at 8:29 pm
  
  Guilin Sun
  Ansys Employee
  
  You are correct that FDTD/RCWA counts all interference effects since it is coherent by nature of the Maxwell Equations.
  If the device is thick and peroid is relatively large, it may induce higher- diffraction orders. Thus the reflection and transmission can be oscillating. You may try to use more number of k vectors to do converging test and see if it is physical, provided that the number of layers are proper, eg the two "ports" are well resolved.
  You may also try to use FDTD for verification with smaller autoshutoff min and much longer simulation time than 1e-5.