Effects of the front surface field in n-type interdigitated back contact silicon heterojunctions solar cells

Previous simulations of interdigitated back contact silicon heterojunction (IBC-SiHJ) solar cells have indicated that front surface passivation is a critical factor in the performance of such cells. This is why we here focus on the effect of a front surface field (FSF) layer by 2D numerical modelling. A FSF layer made of a highly doped thin crystalline silicon top layer makes the cell performance insensitive to the surface recombination velocity up to quite high values (5000 cm/s). It also reduces the lateral resistance losses due to the increased lateral current through the doped layer particularly in IBC-SiHJ solar cells with large pitches. A FSF layer can also be produced by doped hydrogenated amorphous silicon due to the induced accumulation layer at the crystalline silicon surface. The positive effect of such layer strongly depends on the a-Si:H/c-Si interface quality.