Effect of Silver-Assisted Chemical Vapor Etching on morphological properties and silicon solar cell performance

In this work, we report a novel, simple and reproducible etching technique named Silver-Assisted Chemical Vapor Etching method (Ag-ACVE). It consists to expose Ag-loaded silicon substrates to vapors emanating from HF/H2O2 hot solution. The surface treatment performed with this method aims to enhance both optical and electrical properties of conventional silicon solar cells. SEM images of Ag-ACVE treated samples exhibit the appearance of porous micro-cavity like-structure for short etching duration. For long etching duration, sporadic and curved silicon nanowires (SiNWs) were formed. A kinetic study of the vapor etching reaction revealed a relatively high etching rate. Furthermore, the dimension of the micro-cavities increased as a function of the H2O2 molar ratio. UV-Visible measurement showed a significant decrease of the total reflectivity versus the molar ratio. Whereas, at the same time the minority carrier life time was significantly enhanced and as a result the solar cell performance was improved.