The Effect of Tertiary-Butyl Alcohol on the Texturing of Crystalline Silicon Solar Cells

Abstract

The effects of adding different alcohols to the KOH solution used for texturing crystalline silicon have been studied. Instead of using isopropyl alcohol (IPA), the most commonly used alcohol additive in surface texturing, we added tertiary-butyl alcohol (TBA). The use of this alcohol resulted in smaller pyramids forming on the silicon surface. Controlling the surface morphology of the silicon is one of the main concerns when using texturing technology to produce solar cells. It is known that alcohol additives influence the silicon etching rate, in other meaning the etching anisotropy. Due to its low dielectric constant and polarity, TBA reduced the tension of silicon surface. This improved the resulting surface morphology, which consisted of 2 similar to 4 mu m-sized pyramids. We obtained images of surface morphology data using scanning electron microscopy (SEM) and atomic force microscopy (AFM). In addition, surface reflectance was measured by a UV-Vis spectrophotometer.