1. Luminous! Centre of Excellence for Semiconductor Lighting and DisplaysSchool of Electrical and Electronic Engineering and School of Physical and Mathematical SciencesNanyang Technological University Singapore 639798 Singapore
2. Centre for OptoElectronics and Biophotonics (COEB)School of Electrical and Electronic EngineeringThe Photonics Institute (TPI)Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
3. Department of Electrical and Electronics EngineeringDepartment of PhysicsUNAM‐Institute of Materials Science and NanotechnologyBilkent University Ankara 06800 Turkey
4. Division of Physics and Applied PhysicsSchool of Physical and Mathematical SciencesNanyang Technological University Singapore 637371 Singapore