Surface modification of textured silicon and its wetting behaviour

Abstract

Textured silicon (Si) substrate were prepared using various texturing methods both chemical and physical and their water contact angle, surface topography and Raman spectra were studied and investigated. The effect of plasma and chemical treatment on micro/nanostructure and roughness of the surface with and without deposition of Octadecyltrichlorosilane (ODTS, Cl₃Si (CH₃)₁₇), self-assembled monolayer (SAM) is investigated for achieving higher water contact angle (θ_c). The importance of synergism of texturing with deposition of ODTS SAM in preparing superhydrophobic silicon surfaces has been discussed. It is shown that superhydrophobic silicon surfaces can be achieved on silicon surfaces by coating with ODTS, irrespective of whether it is textured or not, polished or unpolished, provided a chemical treatment is given to the surface prior to the ODTS coating.

Keywords:

• TMAH
• KOH
• SF₆
• O₂ plasma
• self-assembled monolayer
• OTS

Acknowledgements

This work was carried out at Nanomaterials and National MEMS design Centre, BITS and Pilani, India. The Author’s thanks Centre for Nanoscience and Engineering (CeNSE), Indian Institute of Science, Bangalore, for their support in providing the fabrication facility.