1. Department of Electrical and Electronics EngineeringDepartment of PhysicsUNAM‐Institute of Materials Science and NanotechnologyBilkent University Ankara 06800 Turkey
2. Luminous! Center of Excellence for Semiconductor Lighting and DisplaysSchool of Electrical and Electronic EngineeringSchool of Physical and Mathematical SciencesSchool of Materials Science and EngineeringNanyang Technological University Singapore 639798 Singapore
3. Department of PhysicsAbant Izzet Baysal University Bolu 14030 Turkey