1. George W. Woodruff School of Mechanical Engineering Institute for Electronics and Nanotechnology Georgia Institute of Technology Atlanta GA 30332 USA
2. Department of Mechanical Engineering University of South Alabama Mobile AL 36608 USA
3. Department of Electrical Computer & Energy Engineering University of Colorado Boulder Boulder CO 80309 USA
4. School of Electrical Engineering Korea Advanced Institute of Science and Technology Daejeon 34141 South Korea
5. George W. Woodruff School of Mechanical Engineering Wallace H. Coulter Department of Biomedical Engineering Institute for Electronics and Nanotechnology Parker H. Petit Institute for Bioengineering and Biosciences Center for Flexible and Wearable Electronics Advanced Research Neural Engineering Center Institute for Materials Institute for Robotics and Intelligent Machines Georgia Institute of Technology Atlanta GA 30332 USA