1. Department of Chemistry King Fahd University of Petroleum & Minerals (KFUPM) Dhahran 31261 Saudi Arabia
2. Center of Research Excellence in Nanotechnology (CENT) King Fahd University of Petroleum & Minerals (KFUPM) Dhahran 31261 Saudi Arabia
3. Physics Department King Fahd University of Petroleum & Minerals Dhahran 31261 Saudi Arabia