1 School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore.
2 Jiangsu Key Laboratory of Thin Films, School of Physical Science and Technology, Soochow University, Suzhou, China.
3 Tim Taylor Department of Chemical Engineering, Durland Hall, Kansas State University, Manhattan, KS, USA.
4 School of Materials Science and Engineering, State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yatsen University, Guangzhou, China.
5 School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore. z.liu@ntu.edu.sg.
7 Centre for Micro-/Nanoelectronics (NOVITAS), School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore. z.liu@ntu.edu.sg.