Understanding the Impact of the Doping Profiles on Selective Emitter Solar Cell by Two-Dimensional Numerical Simulation

The selective emitter (SE) design, featuring lower doped areas between the front contact fingers and higher doped areas underneath the front metallization, is crucial to improve the performance at the front side of a monocrystalline (c-Si) silicon solar cell. One of the most interesting and promising low-cost SE process consists of the screen printing of a phosphorus-doped paste, allowing a separate optimization of the doping profiles in the metallized and nonmetallized front-side areas. By referring to this kind of process, this paper presents a simulation study with a decoupled analysis on the effect of the lowly doped and highly doped profiles on the performance of an SE solar cell, by means of 2-D electro-optical numerical device simulations. Moreover, by exploiting the 2-D modeling, the effect of the alignment tolerance used in the SE diffusion process for the subsequent metallization process has been also investigated. Numerical results show that the adoption of an optimized design for the SE cell can lead to an efficiency improvement above 0.4%_abs compared with the 75 Ω/sq homogeneous emitter reference cell.