1. Photovoltaic Materials and Devices group, Delft University of Technology, Delft 2628 CD, The Netherlands
2. Shenzhen Institute of Wide-bandgap Semiconductors, Shenzhen 518055, China
3. Faculty of Sciences of University of Lisbon, Lisbon 1749-06, Portugal
4. Department of Radiation Science and Technology, Faculty of Applied Sciences, Delft University of Technology, Delft 2629 JB, The Netherlands
5. Institute of Photoelectronic Thin Film Devices and Technology of Nankai University, Tianjin 300350, China