Surface recombination of Si solar cell simulation

Hello

I am working on Si solar cell simulation to get the J-V curve, meanwhile I am thinking to take into accout the surface recombination of the cell. However, the interface of the junctions alway shows not applicable when I applied the Trap assisted surface recombination to the simulation. My queaston is how to address this issue or is that possible to perform surface recombination in COMSOL?

Thanks a lot