A non-metallic additive for diamond-wire-sawn multi-crystalline silicon texturing

¹ Key Laboratory of Solar Thermal Energy and Photovoltaic System of Chinese Academy of Sciences, Institute of Electrical Engineering, The Chinese Academy of Sciences, Beijing, China 100190
² University of Chinese Academy of Sciences, Beijing, China 100049

^a email: wanghe@mail.iee.ac.cn
^* corresponding author:
^b email: zhouchl@mail.iee.ac.cn

Abstract

Diamond-wire-sawn (DWS) technology has been widely used in the photovoltaic industry. When using the HF/HNO₃/H₂O acid etching solution for texturing of DWS multi-crystalline silicon(mc-Si), the aid of additive is required to improve the reactivity of the mc-Si surface in the acid texturing solution. It also needs to enhance the nucleation and uniform growth of the texturing surface. This paper proposes a non-metallic additive for DWS mc-Si texturing. Sodium polyacrylate is added to the HF/HNO₃/H₂O acid etching solution to reduce the reflectance of DWS mc-Si and improve surface morphology. Compared to the textured wafers without additive, the surface of the wafers using this method is uniformly distributed with pits whose size is 0.5 μm×1 μm. And the weighted average reflectance of the textured wafers can be reduced from 33.32% to 23.9% in the wavelength range of 350–1100 nm, with the lowest reflectance of 19.8% reached at 950 nm. It shows a promising application prospect.