Fabrication and Electrowetting Properties of Poly Si Nanostructure Based Superhydrophobic Platform
Poly-silicon based superhydrophobic surface (water contact angle >150°) is being fabricated and its electrowetting properties have been studied. The polysilicon thin film has been deposited over patterned gold electrodes. The polysilicon film is structured to form nanoscale features using Reactive Ion Etching. A thin film of HfO2 high k-dielectric is deposited over the structured polysilicon surface. The surface was chemically modified with Trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane (PFOS). Such a surface showed Superhydrophobic behavior with water contact angle of 172° and roll off angle <3°. The electrowetting properties of the fabricated device was studied by applying a DC voltage between the gold electrode and the droplet. The electrowetting commences when the applied voltage was 18 V and the contact angle is reduced to 152°. As the applied voltage was increased there was decrease in contact angles.
KeywordsSuperhydrophobic surface Contact angle Electrowetting Polysilicon and reactive ion etching
The authors thank for the financial assistance provided by Department of Atomic Energy-Board of Research in Nuclear Science (DAE-BRNS), Government of India. (Sanction No.2012/20/34/6/BRNS). The authors would like to acknowledge the support from Centre of Excellence in Nanoelectronics, Indian Institute of Technology, Bombay, for providing the facility for fabrication and characterization under Indian Nanoelectronics User Program.
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