The Effect of Chemical Texturization Parameters on the Diameter of Pyramids on Silicon Solar Wafers

Light capturing is an essential part of many optical devices such as solar cells. This study aimed at modifying surface reflectivity of silicon solar wafers to improve light trapping. A simple and easily controllable etching technique was used to achieve this objective. The surface topography of silicon wafers was modified by etching a controllable pyramid structure on these surfaces. Potassium hydroxide (KOH) solution was used to etch the silicon surface; the concentrations of KOH were 1mol/L and 2mol/L at temperatures 50°C and 70°C and a varying etching time of 15 and 30 minutes. The surface morphology of the wafer was analyzed by optical microscopy. The activation energy for the reaction was shown to be 42.2 kJ that is very near the value indicated by previous investigators. A texturization mechanism was also advanced using a new parameter that monitors the progressive changes in the diameter of the pyramids. This analysis shows a general increase in the sizes with reduction at certain intervals that can be attributed to the difference in etching rates of the crystal family planes.