1. Department of Electrical and Computer Engineering; University of Arizona; Tucson Arizona 85721
2. Depertment of Electrical Engineering; University of California; Los Angeles, Los Angeles California 90095
3. Center of Excellence for Green Nanotechnologies, King Abdulaziz City for Science and Technology; Riyadh 11442 Saudi Arabia
4. Depertment of Electrical Engineering; University of Southern California; Los Angeles California 90089