Simulation and Optimization of Emitter Depth and Doping for Silicon Solar Cells Under Concentrated Sunlight
Abstract
Higher concentration of sun light increases the amount of current and lower sheet resistance is needed to decrease the loss of current flow. Two ways can be considered for having lower sheet resistance: increasing the doping concentration and the depth of emitter region, but both of them may decrease the efficiency in some values. If we consider both methods simultaneously, the optimum values for doping concentration and emitter depth will change. Another suggestion for improving the efficiency is placing n+-layer under the contacts. In this work, we simulate a common structure of silicon solar cell in different sunlight concentrations. Sunlight concentration causes different behaviors in different emitter doping concentrations and depths. These behaviors are studied by examining some physical phenomena occur during the cell operation. Thus, the optimum value for doping concentrations and depths and qualitative reasons for the changes can be determined. In addition, we compare the results with analytical description in some cases. Additionally, we simulate the n+-layer under the contacts and compare the efficiency of that with previous condition, its influence is more considerable in higher sheet resistances.