1. Graduate Institute of Photonics and Optoelectronics, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
2. Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan
3. Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan
4. Graduate Institute of Electronics Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
5. Department of Electrical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan