Hydrophobic coating of GaAs surfaces with nanostructured ZnO

Avoiding dew from the exterior of solar panels is of importance since this may reduce the number of photons hitting the surface. The hydrophilic/hydrophobic coating of GaAs surface with nanostructured ZnO was done by the ultrasound assisted method with the addition of templating agents such as polyvinyl pyrrolidone (PVP), polyethylene glycol (PEG), dodecylamine (DDA), or hexatetramethylene tetramine (HMTA). The best hydrophobic properties and contact angle of 141 were obtained when DDA stabilized ZnO layers were coated on the GaAs. The stability to the scotch-tape test and to outdoor exposure for at least 2 weeks was demonstrated. The XRD, SEM and AFM studies revealed the formation of hierarchical structure consisting of ZnO nanoparticles. The water repulsion effect is explained as being due to the high roughness of the pyramidal shaped layer. (C) 2016 Elsevier B.V. All rights reserved.