Interface recombination in amorphous/crystalline silicon solar cells, a simulation study

The paper presents a numerical simulation of the behavior of a-Si:H/c-Si heterojunction solar cells. The simulations address in particular the question of the role of interface recombination for the device performance. It is shown that the critical parameters are the density of interface states at the a-Si:H/c-Si heterojunction and the band bending which is determined by the band offsets and the front contact work function. It is shown that due to the more favorable band bending the structure with the p-type emitter on an n-type c-Si absorber has an intrinsic advantage over the inverse structure. The role of an undoped a-Si:H buffer layer is discussed and it is shown that the front contact TCO/a-Si:H has considerable influence on the band bending in the c-Si wafer and therefore is of crucial importance for the cell performance.