1. Department of Electronics and Telecommunications, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
2. Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
3. Oak Ridge National Laboratories, P.O. Box 2008 MS 6123, Oak Ridge, Tennessee 37831, United States
4. Department of Chemical Engineering and Materials Science, University of California—Davis, Davis, California 95616, United States