1. Department of Materials Science and Engineering Korea University Seoul 02841 Republic of Korea
2. Department of Materials Science and Engineering Massachusetts Institute of Technology Cambridge MA 02139 USA
3. Department of Physics Korea Advanced Institute of Science and Technology Daejeon 34141 Republic of Korea
4. LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays School of Electrical and Electronic Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
5. ARC Centre of Excellence in Exciton Science Department of Materials Science and Engineering Monash University Clayton Campus Melbourne Victoria 3800 Australia
6. Department of Semiconductor Systems Engineering Korea University Seoul 02841 Republic of Korea
7. School of Physical and Mathematical Sciences Nanyang Technological University Singapore 639798 Singapore
8. Department of Electrical and Electronics Engineering and Department of Physics UNAM‐Institute of Materials Science and Nanotechnology Bilkent University Bilkent Ankara 06800 Turkey