Cao, Yameng and Robson, Alexander James and Alharbi, Abdullah and Roberts, Jonny and Woodhead, Christopher and Noori, Yasir and Bernardo Gavito, Ramon and Roedig, Utz and Falko, Vladimir and Young, Robert James (2017) Optical identification using imperfections in 2D materials. 2D Materials, 4 (4): 045021. ISSN 2053-1583
cao_et_al_2017_2D_Mater._10.1088_2053_1583_aa8b4d.pdf - Accepted Version
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Abstract
The ability to uniquely identify an object or device is important for authentication [1]. Imperfections, locked into structures during fabrication, can be used to provide a fingerprint that is challenging to reproduce. In this paper, we propose a simple optical technique to read unique information from nanometer-scale defects in 2D materials. Imperfections created during crystal growth or fabrication lead to spatial variations in the bandgap of 2D materials that can be characterized through photoluminescence measurements. We show a simple setup involving an angle- adjustable transmission filter, simple optics and a CCD camera can capture spatially- dependent photoluminescence to produce complex maps of unique information from 2D monolayers. Atomic force microscopy is used to verify the origin of the optical signature measured, demonstrating that it results from nanometer-scale imperfections. This solution to optical identification with 2D materials could be employed as a robust security measure to prevent counterfeiting.