1. Dept. of Solar Energy and Environmental Physics, Jacob Blaustein Institutes for Desert Research; Ben-Gurion University of the Negev; SedeBoker campus 84990 Israel
2. Ilze Kats Institute for Nanoscale Science and Technology; Ben-Gurion University of the Negev; Beer-Sheva 84105 Israel
3. Dept. of Chemical Eng.; Ben-Gurion University of the Negev; Beer-Sheva 84105 Israel