1. Department of Materials Science and Engineering, Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA
2. Department of Electrical Engineering, Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA
3. School of Urban Development and Environmental Engineering, Shanghai Second Polytechnic University, Shanghai 201209, P. R. China
4. Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA
5. Department of Mechanical Engineering and Materials Science and Engineering Program, University of Texas at Austin, One University Station C2200, Austin, TX 78712, USA