Exfoliating Bismuth to get thin films

We focused on trying to exfoliate bismuth the same way that graphite was exfoliated to see if we could get 50 nm thick films of bismuth. We first used mechanical exfoliation to see if exfoliation was possible with bismuth. Next we tried liquid exfoliation to see if the we could exfoliate with that method. Also we compared the exfoliation of bismuth telluride to the exfoliation of bismuth. Introduction The purpose of the experiment is to see if is possible to use mechanical and liquid exfoliation for bismuth. Bismuth is a 2D topological insulator because the orbit of the spin orbit effect is too big for the material so the electrons are pushed to the edge. So there is only conducting on the surface. This happens at 50 nm or lower thanks to quantum confinement. Bismuth Telluride is 3D topological insulator that has a spinmomentum that has a narrow energy gap and a semiconductor material and has a hexagonal layered structure. This research could help in the field of spintronics. Results for Bismuth Sandpaper Crushing between glass Scotch Tape 20kV x370 50μm 20kV x250 100μm 20kV x270 50μm Results for Bismuth Telluride Used ultrasonication and liquid exfoliation for the bismuth telluride. The solvent used as the liquid is n-methyl pyrrodilone. 20x magnification using Olympus Microscope. Exfoliated Bismuth Telluride Conclusion From the images that we got from the scanning electron microscope we could not exfoliate 50 nm of bismuth by mechanical or liquid exfoliation. Acknowledgements • Mentors : Dr. Tito Huber and Dr. Scott Johnson • Faulty and staff at Howard Nanoscale Science and Engineering Facility(HNF) at Howard University • National Science Foundation PRDM Program References • A.K. Geim and I.V. Grigorieva, “Van der Waals heterostructures,” Nature 499 419 (2013). • D. Teweldebrhan, V. Goyal, and A.A. Balandin, “Exfoliation and Characterization of Bismuth Telluride Atomic Quintuples and Quasi-Two-Dimensional Crystals,” Nano Lett. 10 120 (2010). • I. K. Drozdoz, A. Alexandradinata, S. Jeon1, S. Nadj-Perge1, H. Ji, R. J. Cava B. A. Bernevig, and A. Yazdani, “One-dimensional Topological Edge States of Bismuth Bilayers,” arxiv 14.04 2598v1 • J. N. Coleman. “Liquid exfoliation of defect-free graphene,” Acc. Chem. Res. 46 14 (2013). • K. S. Novoselov, A.K. Geim, S.V. Morozov, D. Jiang, Y. Zhang, S.V. Dubonos, I.V. Grigorieva, and A. A. Firsov, “Electric Field Effect in Atomically Thin Carbon Films,” Science 306 666 (2004). • S. Murakami. “Phase transition between the quantum spin Hall effect and insulator phases in 3D emergence of a topological gapless phase,” New J. Phys. 9 356 (2007). • V. Nicolosi, M. Chholowalla, M.G. Kanatzidis, M.S. Strano, and J.N. Coleman. “Liquid Exfoliation of Layered Materials,” Science 34