[1] Univ Illinois, Dept Mat Sci & Engn, Urbana, IL 61801 USA
[2] Univ Illinois, Dept Phys, Urbana, IL 61801 USA
[3] Univ Illinois, Dept Engn Sci & Mech, Urbana, IL 61801 USA
[4] Univ Illinois, Dept Elect & Comp Engn, Urbana, IL 61801 USA
[5] Univ Illinois, Dept Chem, Urbana, IL 61801 USA
[6] Univ Illinois, Beckman Inst Adv Sci & Technol, Urbana, IL 61801 USA
[7] Univ Illinois, Frederick Seitz Mat Res Lab, Urbana, IL 61801 USA
[8] Purdue Univ, Sch Elect & Comp Engn, W Lafayette, IN 47907 USA
[9] Lehigh Univ, Dept Phys, Bethlehem, PA 18015 USA
[10] Lehigh Univ, Ctr Adv Mat & Nanotechnol, Bethlehem, PA 18015 USA