1. Institute of Micro-Nano Devices and Solar Cells College of Physics and Information Engineering Fuzhou University Fuzhou 350108 Fujian P. R. China
2. Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108 Fujian P. R. China
3. Electronics and Information Science Fujian Jiangxia University Fuzhou 350108 Fujian P. R. China
4. Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering Changzhou 213164 Jiangsu P. R. China