1. Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Provincial Key Laboratory of Photonics & Information Technology Xi'an Jiaotong University Xi'an 710049 China
2. School of Electronic Science and Engineering Xi'an Jiaotong University Xi'an 710049 China
3. Research and Development Center for Solid State Lighting Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 China
4. National Centre for International Joint Research of Electronic Materials and Systems School of Information Engineering Zhengzhou University Zhengzhou 450001 China
5. Institute of Materials and Systems for Sustainability Nagoya University Nagoya Aichi 464‐8601 Japan
6. Department of Electronic and Electrical Engineering University of Sheffield Mappin Street Sheffield S1 3JD UK
7. School of Microelectronics Xidian University Xi'an 710126 China