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, and Sunmin Ryu*

육방정계 질화붕소(hBN)는 다양한 전자·광학 소자에 활용되는 중요한 이차원 물질이지만, 넓은 면적에서 결정 구조와 도메인 특성을 비파괴적으로 정밀 분석하는 데에는 한계가 있었다. 본 연구에서는 간섭 기반 2차 고조파 발생(SHG) 이미징과 편광 분석을 이용해 hBN 박막 내 역평행 도메인과 그 경계를 광학적으로 식별하고, SHG 및 라만 분광의 상관관계를 바탕으로 결정성과 구조적 불균일성을 평가할 수 있음을 보였다. 본 연구 결과는 2026년 4월 1일 Advanced Materials에 게재되었다.

 Hexagonal boron nitride (hBN) supports a wide range of 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, non-destructive probe of lattice orientation and structural integrity in 2D hBN grown by chemical vapor deposition. 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.

https://advanced.onlinelibrary.wiley.com/doi/10.1002/adma.202519546