The effect of geometrical sizes on efficiency of vertical silicon tunnel junction solar cell for high solar concentration

Abstract

In the paper the effect of height, base width and doping level on efficiency of the silicon vertical solar cell with two p-n junctions connected by tunnel junction, is investigated by 2D simulations. It is shown that the dependence efficiency on the height of p-n junction has non monotonic behavior. It is attributed to impact of high solar concentration on distribution of effective electric field normal to p-n junction border in the n-base of vertical solar cell. The distribution of the field depend on the height of p-n junction at high solar concentration. Efficiency is increased with increasing the width of base up to 25 $\mu$m. Increasing of the efficiency with decreasing the base doping level is connected with increasing the carrier mobility. Dependence of the efficiency on solar concentration is also considered. Efficiency is reached the saturation at solar concentration around 1000 suns.