1. Institute of Materials Science and Applied Research, Vilnius University, Saulėtekio al. 9, Building III, LT‐2040 Vilnius, Lithuania
2. Graduate Institute of Electro‐Optical Engineering and Department of Electrical Engineering, National Taiwan University 1, Roosevelt Road, Sec. 4, Taipei, Taiwan, R.O.C
3. Advanced Epitaxy Technology Inc., Hsinchu Industrial Park, Hsinchu, Taiwan, R.O.C