Electrochemical-induced morphological formation and optical properties of p-type silicon wafer

Abstract

The enhancement of light absorption and surface area in monocrystalline solar cells is achieved through anisotropic etching, with the aim of improving its conversion efficiency. Nevertheless, the conventional method of anisotropic etching is constrained in its capacity for incrementing surface area. Herein, a promising texturization process in the form of a homogenous and uniform pyramidal structure is proposed with two-step texturing processes: cyclic voltammetry (CV) treatment and the alkali anisotropic etching method on the silicon wafer surface. Prior to and following the alkali texturing process, the silicon surface was modified using the CV treatment. The effect of this approach was investigated under different CV cycles (20, 40, 60 and 80 cycles) in a 0.5 M Na₂SO₄ aqueous electrolyte with pH ~ 7. Based on the field emission scanning electron microscope (FESEM) micrographs and UV-visible spectrometer (UV-Vis) measurements, the wafer textured with 60 cycles of CV treatment and an alkali anisotropic etching process tremendously improves the surface morphology and decreases the front surface reflection. As a result, the size and height of the pyramid formed were 2.1–2.3 µm and 0.6–1.9 µm, respectively. Moreover, the outlined methodology facilitates a substantial decrease in surface damage and is applicable in the Si texturization process for the manufacturing of solar cells.