[1] Department of Materials Science and Engineering, Stony Brook University, Stony Brook, NY 11794-2275, United States
[2] Department of Electrical Engineering and Center for Solid State Electronics Research, Arizona State University, Tempe, AZ 85287-5706, United States
[3] Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695-7907, United States
[4] School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0250, United States