Thin, light-absorbing films attenuate the Raman signal of underlying substrates. In this article, we exploit this phenomenon to develop a contactless thickness profiling method for thin films deposited on rough substrates. We demonstrate this technique by probing profiles of thin amorphous silicon stripes deposited on rough crystalline silicon surfaces, which is a structure exploited in high-efficiency silicon heterojunction solar cells. Our spatially-resolved Raman measurements enable the thickness mapping of amorphous silicon over the whole active area of test solar cells with very high precision; the thickness detection limit is well below 1 nm and the spatial resolution is down to 500 nm, limited only by the optical resolution. We also discuss the wider applicability of this technique for the characterization of thin layers prepared on Raman/photoluminescence-active substrates, as well as its use for single-layer counting in multilayer 2D materials such as graphene, MoS2 and WS2.
|Original language||English (US)|
|State||Published - Dec 6 2016|
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was supported by the Czech Science Foundation Project 14–15357S and by the Czech Ministry of Education, Youth and Sports Project LM2015087, by the Swiss Commission for Technology and Innovation under Grant 17705.1, and by Meyer Burger Research. The research reported in this publication was supported by funding from King Abdullah University of Science and Technology (KAUST). Finally, partial support of the H2020-LCE project H2020-LCE (no. 727523) is acknowledged.