1. School of Engineering, The Australian National University (ANU), Canberra, ACT 2601, Australia
2. SIMS and Microscopy Facility, Western Sydney University, Sydney, NSW 2753, Australia
3. Department of Electrical and Electronic Engineering, University of Melbourne, Melbourne, VIC 3010, Australia
4. Jinko Solar Co., Ltd., Shangrao, Jiangxi Province 334100, China