Acknowledgements: Zhuotong Sun, Ming Xiao, and Judith L. MacManus-Driscoll thank the Royal Academy of Engineering grant, CIET1819_24, for funding. Subhajit Bhattacharjee thanks the Cambridge Trust (HRH The Prince of Wales Commonwealth Scholarship) for funding. Judith L. MacManus-Driscoll and Rob Jagt also thank Bill Welland for funding, as well as EPSRC grant EP/N509620/1 for funding a PhD studentship. Megan Hill thanks the Herchel Smith Foundation for a research fellowship. Kevin Musselman and Louis-Vincent Delumeau thank the Canada Foundation for Innovation Exceptional Opportunities Fund, Project 41017, for funding. The authors also thank Babak Bhakit for facilitating the ToF-ERDA analysis of the film, Yang Li on Raman characterization, and Qingshen Jing and Nives Strkalj for fruitful discussion on the figures.