Effect of high frequency vibrations on PV silicon purification

Abstract Silicon purification for photovoltaic applications is a crucial challenge to improve the energy production performance of solar panels. In the present work, we focus on the metallurgical grade silicon purification process through a directional solidification technique, namely the horizontal Bridgman technique. By means of numerical simulations, it is shown that high frequency vibrations applied to the crucible can be used to enhance the convective level in the molten silicon (thermal-vibrational effect) and improve the purification of the final silicon ingot. The direction of the vibration, however, has to be carefully chosen, as it strongly influences the flow intensity and structure in the melt and can lead to multi-rolls and even reverse flows, with a direct effect on the induced purification.