1. University of Oklahoma, School of Electrical and Computer Engineering, Norman, Oklahoma 73019, United States
2. University of Oklahoma, School of Electrical and Computer Engineering, Norman, Oklahoma 73019, United StatesbUniversity of Oklahoma, Homer L. Dodge Department of Physics and Astronomy, Norman, Oklahoma 73019, United States
3. University of Oklahoma, Homer L. Dodge Department of Physics and Astronomy, Norman, Oklahoma 73019, United States
4. IQE, Inc., 119 Technology Drive, Bethlehem, Pennsylvania 18015, United States