1. Department of Mechanical Engineering and the Materials Science and Engineering Program, The University of Texas at Austin, 1 University Station C2200, Austin, Texas 78712, United States
2. Microelectronics Research Center and Department of Electrical Engineering, The University of Texas at Austin, Austin, Texas 78758, United States
3. CNR-IDASC Sensor Lab Department of Chemistry and Physics, University of Brescia, via Valotti, 9, Brescia 25133, Italy
4. Department of Organic and Nano System Engineering, Konkuk University, Seoul 143-701, South Korea
5. Department of Materials Science and Engineering, Inha University, Incheon 402-751, South Korea
6. Department of Physics, Xiamen University, Xiamen 361005, People’s Republic of China