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arXiv · 2509.25910

Ubiquitous Antiparallel Domains in 2D Hexagonal Boron Nitride Uncovered by Interferometric Nonlinear Optical Imaging

Yeri Lee·Juseung Oh·Kyung Yeol Ma·Seung Jin Lee·Eui Young Jung·Yani Wang·Kenji Watanabe·Takashi Taniguchi·Hailin Peng·Hiroki Ago·Ki Kang Kim·Hyeon Suk Shin·Sunmin Ryu
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Abstract

Hexagonal boron nitride (hBN) supports a wide range of two-dimensional (2D) technologies, yet assessing its crystalline quality over large areas remains a fundamental challenge. Both antiparallel domains, an intrinsic outcome of epitaxy on high-symmetry substrates, and associated structural defects have long evaded optical detection. Here, we show that interferometric second-harmonic generation (SHG) imaging provides a powerful, nondestructive probe of lattice orientation and structural integrity in chemical vapor deposition-grown hBN. This approach reveals the ubiquitous formation of antiparallel domains and quantifies their impact on crystalline order. SHG intensity also emerges as a direct optical metric of domain disorder, spanning three orders of magnitude across films produced by ten different growth routes. Correlation with Raman spectroscopy establishes a unified framework for evaluating crystalline quality. Beyond hBN, this method offers a high-throughput route to wide-area structural imaging in various non-centrosymmetric materials, advancing their deployment in electronics, photonics, and quantum technologies.

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Yeri Lee, Juseung Oh, Kyung Yeol Ma, Seung Jin Lee, Eui Young Jung, Yani Wang, Kenji Watanabe, Takashi Taniguchi, Hailin Peng, Hiroki Ago, Ki Kang Kim, Hyeon Suk Shin, Sunmin Ryu. 2025-09-30. Ubiquitous Antiparallel Domains in 2D Hexagonal Boron Nitride Uncovered by Interferometric Nonlinear Optical Imaging. https://doi.org/10.1002/adma.202519546

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