1. Center of Research Excellence in Nanotechnology (CENT) King Fahd University of Petroleum & Minerals KFUPM Box 5040 Dhahran 31261 Saudi Arabia
2. Physics Department King Fahd University of Petroleum & Minerals KFUPM Box 5047 Dhahran 31261 Saudi Arabia
3. Chemistry Department King Fahd University of Petroleum & Minerals Dhahran 31261 Saudi Arabia
4. Department of Material Chemistry Graduate School of Engineering Kyoto University Nishikyo-ku Kyoto 615-8520 Japan