A question of polytype control and quality: from heteroepitaxy to homoepitaxy of boron nitride

Johannes Binder
University of Warsaw – Warsaw, Poland
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Hexagonal boron nitride (hBN) is a two-dimensional (2D) material and a member of the III-nitride family that has recently attracted great interest due to its versatile range of applications, for example as hydrogen barrier¹, UV light source_², tunnelling barrier^3, single-photon emitter⁴, excellent substrate for growth and gating of other 2D materials⁵, as membrane leading to polarisation-dependent Raman enhancement⁶ and for quantum sensing applications⁷. However, despite significant efforts by many research groups worldwide to improve growth, non-native substrates remain a fundamental factor that limits the quality. This problem can be solved by homoepitaxy, which is the growth of hBN on hBN substrates. In this work⁸, we demonstrate the homoepitaxial growth of triangular BN grains on exfoliated hBN (see Fig. 1) by Metal-Organic Vapour Phase Epitaxy and show by atomic force microscopy and photoluminescence that the BN stacking order is enforced by the crystallographic direction of the edge of the exfoliated hBN flakes (armchair edges – centrosymmetric; zigzag edges non-centrosymmetric BN polytypes). These findings are important as non-centrosymmetric BN polytypes^9,10 enable properties like piezoelectricity or
ferroelectricity. Our results hence indicate possible pathways to grow homoepitaxial BN with tuneable layer stacking, which is required to deterministically induce piezoelectricity or ferroelectricity in future
heterostructures.

[1] J. Binder et al. Nano Letters 23, 1267 (2023)
[2] K. P. Korona, J. Binder et al. Nanoscale,15, 9864 (2023)
[3] J. Binder et al. Nature Communications 10:2335 (2019)
[4] M. Koperski et al. Scientific Reports 11:15506 (2021)
[5] K. Ludwiczak et al. ACS AMI, 16, 49701 (2024)
[6] J. Rogoza, J. Binder et al. Nanoscale published online – doi:10.1039/D4NR03091E (2025)
[7] T. Clua-Provost et al. Phys. Rev. Lett. 131, 126901 (2023)
[8] J. Binder et al. Nano Letters, 24, 6990 (2024)
[9] J. Iwanski et al. npj 2D Materials and Applications 8:72 (2024)
[10] A. Rousseau et al. ACS Nano 16, 2756 (2022)

Email: johannes.binder@fuw.edu.pl