Dear Adnan Javed

I think that your question is not clear. If you asked like that "What does absorption model means in solar cell simulation?", I can answer it briefly.

There are many optical models in simulation but four of them are used mainly:

1. Transfer Matrix Method (TMM)

2. Ray Tracing

3. Rigorious coupled wave analysis (RCWA)

4. Finite difference time domain (FDTD)

First of all, we need to know about our solar cell structure. If you have textured structure, you can use only Ray tracing because it includes population of rays. For nanophotonic solar cells, which includes nanoparticles, quantum dots or nanograting, RCWA and FDTD can be used. For think planar layer structure, TMM is the best choice because it can consider internal interference in think layers.

Above models includes surface reflections also. But there is another simpler model which is "Burger-Lambert" absorption model. It calcualtes only absorption of the light in medium and doesn't consider surface reflections.

Note, TMM and Ray trancing also includes the bureger lambert equation, they are more advanced optical simulation models than just absorption model. In RCWA and FDTD, Maxwell equations are solved directly and they don't include Burger Lambert model.

Jasurbek Gulomov