1. Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan
2. Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
3. Department of Opto-Electronic Engineering, National Dong Hwa University, Hualien 974301, Taiwan
4. Department of Electrical Engineering, Yuan Ze University, Taoyuan 32003, Taiwan