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Surface texture and optical properties of crystalline silicon substrates

2015; American Institute of Physics; Volume: 7; Issue: 6 Linguagem: Inglês

10.1063/1.4937117

1941-7012

Adebayo A. Fashina, Kenneth Kennedy Adama, Oluwaseun K. Oyewole, Vitalis C. Anye, Joseph Asare, M. G. Zebaze Kana, W. O. Soboyejo,

Silicon and Solar Cell Technologies

This paper presents the results of an experimental study of the effects of surface texture on the optical and light trapping properties of silicon wafers. Surface texture is controlled by anisotropic etching with potassium hydroxide (KOH) and isopropyl alcohol (IPA) solutions. The anisotropic etching of (001) crystalline silicon wafers is shown to result in the formation of {111} pyramidal facets on the surfaces of the wafers. A combination of profilometry, optical microscopy, scanning electron microscopy, and atomic force microscopy is used to study the effects of KOH/IPA etching on the morphology and roughness of the textured surfaces. The results show that IPA concentration has the strongest effect on the surface roughness of (001)-single crystal crystals at temperatures up to 80 °C. Above this value, evidence of temperature-induced cracking was revealed on the silicon substrate. The best volume concentration ratio of KOH:IPA is also found to be 2:4. The implications of the study are discussed for the design of light trapping in silicon solar cells.