Optimization of textured structure on crystalline silicon wafer for heterojunction solar cell

Increasing the light scattering in monocrystalline silicon solar cells by surface texturing is an emerging field of practice in modern silicon photovoltaic. In this article, the surface micro-textures were performed on the monocrystalline silicon surface in potassium hydroxide solution without adding isopropyl alcohol. The parameters of the etching process such as concentration, time duration and temperature were examined to study the effects on shape and geometry of the microstructure. In addition, ray-tracing simulations of the light trapping were performed on these textured structures. The textured surfaces resemble the structures of uniform pyramids, mostly small pyramids, and mostly big pyramids. The simulation technique was applied in order to evaluate the light trapping effect by textured surfaces based on above pyramidal shape models. Afterwards, theoretical and experimental values of reflection data were compared. Such a simulation model was perceived as an effective tool for optimizing the micro structural shape, thus improving the light trapping. In this study, for solar cell applications, the double-side heterojunction solar cell with mostly big pyramids shape yielded an active area conversion efficiency of 16.3% with an open circuit voltage of 0.645 V, a short circuit current of 34.8 mA cm−2 and a fill factor of 0.73.

► Optical simulation technique was applied to evaluate the light trapping effect by textured surfaces. ► The reflection of mostly big pyramids shape was better than that of the other two shapes. ► Double side HJ solar cells with efficiency of 16.3% were fabricated with an optimal textured Si substrate.