Analysis optical contribution of rear passivation layer to photo- generated current of silicon solar cell with numerical simulation

For high efficiency solar cell, both side of passivation layer is necessary for achieving high open circuit voltage. Generally, passivation layer reduces recombination site of silicon surface, thereby increasing lifetime of carriers. Also, in case of front passivation layer, it reduces reflectance so light could be more absorbed to Si substrate than without passivation layer. On the other side, rear side of solar cell, rear metal electrode is located which is highly reflective. So, it is difficult to experimentally demonstrate optical contributions of rear passivation layer. In this paper, using numerical optic simulation which based on transfer matrix method, we calculate reflectance of solar cell which have rear passivation layers. For improving light trapping effects in solar cell. We design two different solar cell structures which have different type of rear passivation layer. Single layer structure consists only two rear passivation layers in rear side of solar cell. Multiple layer structure consists of repeated two different thin oxide layer 12 times. We calculate reflectance of two structures with simulation tool and compare the optical effect of rear passivation layers. Through this, we can optimize the condition of rear passivation layer for highest efficiency.