Design of experiment approach to the optimization of diffusion process on nanoscopic silicon solar cell

Abstract

The temperature and duration of diffusion process were optimized for fabricating nanoscopic silicon based solar cells using design of experiments (DoE) technique. The optimum nano-structure silicon substrate had been etched for 180s and had porosity of 25%, depth of 0.34 μm and diameter of 99.8 nm. Modeling and experimental design were implemented by D-optimal design of experiment with 12 random experiments. The temperature and time parameters were varied at ranges of 810–910 °C and 15–60 min, respectively. The result indicated that the diffused substrate at temperature of 840 °C and time of 60 min had the highest voltage and current-density which were 0.607 V and 24.32 mA/cm2, respectively. The reflectance of fabricated optimum solar cell was gaged. The result presented that the reflectance of black silicon solar cell had been 600 times less than the non-porous solar cells using SiNx coated polished surface as antireflection layer. In addition, considerable gains of 13.64% on average efficiency, 0.53 on fill factor, 0.611 V on open circuit voltage and 43.43 mA/cm2 on current-density were achieved for optimum black silicon solar cell.