1. Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research); 3 Research Link Singapore 117602
2. Microelectronics Research Centre; The University of Texas at Austin; Austin TX 78758 USA
3. Institute of Chemistry; Academica Sinica; Taipei 11529 Taiwan Republic of China
4. Department of Mechanical Engineering; National University of Singapore; Block EA #07-08, 9 Engineering Drive 1 Singapore 117576