Polytypism in ultrathin tellurium
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Apte, A., Bianco, E., Krishnamoorthy, A., Yazdi, S., Rao, R., Glavin, N., Kumazoe, H., et al. (2019). Polytypism in ultrathin tellurium. 2D Materials, 6 (1)https://doi.org/10.1088/2053-1583/aae7f6
We report the synthesis of ultrathin tellurium films, including atomically thin tellurium tri-layers, by physical vapor deposition (PVD) as well as larger area films by pulsed laser deposition (PLD). PVD leads to sub-nanometer, tri-layer tellurene flakes with distinct boundaries, whereas PLD yields uniform and contiguous sub-7 nm films over a centimeter square. The PLD films exhibit the characteristic hexagonal crystal structure of semiconducting tellurium, but high resolution transmission electron microscopy (HRTEM) reveals a unique stacking polytype in the thinner PVD-grown material. Density Functional Theory calculations predict the possible existence of three polytypes of ultrathin Te, including the α-type experimentally observed here. The two complementary growth methods afford a route to controllably synthesize ultrathin Te with thicknesses ranging from three atomic layers up to 6 nm with unique polytypism. Lastly, temperature dependent Raman studies suggest the possible coexistence of polymorphs.
External DOI: https://doi.org/10.1088/2053-1583/aae7f6
This record's URL: https://www.repository.cam.ac.uk/handle/1810/287093