1. Ilse Katz Institute for Nanoscale Science and Technology; Ben-Gurion University of the Negev; Be'er Sheva 8410501 Israel
2. Department of Solar Energy and Environmental Physics; Swiss Institute for Dryland Environmental and Energy Research; Jacob Blaustein Institutes for Desert Research; Ben-Gurion University of the Negev; Midreshet Ben-Gurion 8499000 Israel
3. Department of Materials Engineering; Ben-Gurion University of the Negev; Be'er Sheva 8410501 Israel
4. Department of Electro-Optics Engineering; Ben-Gurion University of the Negev; Be'er Sheva 8410501 Israel
5. Department of Physics; Nuclear Research Center Negev; P.O. Box 9001 Be'er Sheva Israel