Texturization of as-cut p-type monocrystalline silicon wafer using different wet chemical solutions

Abstract

Implementing texturization process on the monocrystalline silicon substrate reduces reflection and enhances light absorption of the substrate. Thus texturization is one of the key elements to increase the efficiency of solar cell. Considering as-cut monocrystalline silicon wafer as base substrate, in this work different concentrations of Na2CO3 and NaHCO3 solution, KOH–IPA (isopropyl alcohol) solution and tetramethylammonium hydroxide solution with different time intervals have been investigated for texturization process. Furthermore, saw damage removal process was conducted with 10% NaOH solution, 20 wt% KOH–13.33 wt% IPA solution and HF/nitric/acetic acid solution. The surface morphology of saw damage, saw damage removed surface and textured wafer were observed using optical microscope and field emission scanning electron microscopy. Texturization causes pyramidal micro structures on the surface of (100) oriented monocrystalline silicon wafer. The height of the pyramid on the silicon surface varies from 1.5 to 3.2 µm and the inclined planes of the pyramids are acute angle. Contact angle value indicates that the textured wafer’s surface fall in between near-hydrophobic to hydrophobic range. With respect to base material absolute reflectance 1.049–0.75% within 250–800 nm wavelength region, 0.1–0.026% has been achieved within the same wavelength region when textured with 0.76 wt% KOH–4 wt% IPA solution for 20 min. Furthermore, an alternative route of using 1 wt% Na2CO3–0.2 wt% NaHCO3 solution for 50 min has been exploited in the texturization process.