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HL: Fachverband Halbleiterphysik
HL 26: Poster 2D Materials Beyond Graphene: Growth, Structure and Substrate Interaction (joint session O/HL)
HL 26.4: Poster
Dienstag, 18. März 2025, 13:30–15:30, P3
Incommensurability and negative thermal expansion of single-layer hexagonal boron nitride — •Marko Kriegel1, Karim Omambac1, Steffen Franzka2, Frank Meyer zu Heringdorf1,2, and Michael Horn-von Hoegen1 — 1Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Lotharstr. 1, 47057 Duisburg, Germany — 2Interdisciplinary Center for Analytics on the Nanoscale (ICAN), Carl-Benz-Str. 199, 47057 Duisburg, Germany
The emerging field of straintronics, i.e., the control and utilization of the strain state of 2D-materials, is of great importance for their technological development, specifically in view of their future incorporation into van der Waals heterostructures. To gain fundamental insight into structural peculiarities of two-dimensional systems, single-layer hexagonal boron nitride (hBN) grown on Ir(1 1 1) by chemical vapor deposition was used as a prototypical model system: High-resolution reciprocal space mapping reveals the incommensurate nature of the material system by measuring the hBN in plane lattice parameter with high precision, facilitated by the moiré magnification effect in electron diffraction. In a growth temperature (Tg) regime of 700 to 1150∘C an average lattice parameter of 2.496 ± 0.006 Å was found. Eventually, careful disentanglement of the hBN and substrate behavior for rising Tg allowed the determination of a negative thermal expansion coefficient of αhBN = 2.4 ± 1.2×10−6 K−1 for free-standing hBN.[1] [1] M. Kriegel et al. Appl. Surf. Sci. 624 (2023) 157156
Keywords: single-layer growth; Chemical vapor deposition; 2D Hexagonal boron nitride; Negative thermal expansion; Lattice parameter