Pressure‐Induced Formation and Mechanical Properties of 2D Diamond Boron Nitride

Autor: Filippo Cellini, Francesco Lavini, Elton Chen, Angelo Bongiorno, Filip Popovic, Ryan L. Hartman, Remi Dingreville, Elisa Riedo
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Advanced Science, Vol 8, Iss 2, Pp n/a-n/a (2021)
Druh dokumentu: article
ISSN: 2198-3844
DOI: 10.1002/advs.202002541
Popis: Abstract Understanding phase transformations in 2D materials can unlock unprecedented developments in nanotechnology, since their unique properties can be dramatically modified by external fields that control the phase change. Here, experiments and simulations are used to investigate the mechanical properties of a 2D diamond boron nitride (BN) phase induced by applying local pressure on atomically thin h‐BN on a SiO2 substrate, at room temperature, and without chemical functionalization. Molecular dynamics (MD) simulations show a metastable local rearrangement of the h‐BN atoms into diamond crystal clusters when increasing the indentation pressure. Raman spectroscopy experiments confirm the presence of a pressure‐induced cubic BN phase, and its metastability upon release of pressure. Å‐indentation experiments and simulations show that at pressures of 2–4 GPa, the indentation stiffness of monolayer h‐BN on SiO2 is the same of bare SiO2, whereas for two‐ and three‐layer‐thick h‐BN on SiO2 the stiffness increases of up to 50% compared to bare SiO2, and then it decreases when increasing the number of layers. Up to 4 GPa, the reduced strain in the layers closer to the substrate decreases the probability of the sp2‐to‐sp3 phase transition, explaining the lower stiffness observed in thicker h‐BN.
Databáze: Directory of Open Access Journals
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