Efficient Screening of Long-Wavelength Interfacial Moiré Superlattices in Self-Folded Two-Dimensional Materials

Abstract

Moiré superlattices at two-dimensional (2D) material interfaces enable emergent electronic, electrical, and optical phenomena, yet their preparation remains constrained by complex fabrication and limited throughput. Here, we transform the preparation of hexagonal boron nitride (hBN) moiré homojunctions from a fabrication challenge into a classification problem by directly identifying parallel-stacked moiré samples with long wavelengths from spontaneously self-folded flakes following tape exfoliation. By exploiting the intrinsic cleavage behavior and wrinkle formation of layered materials, this strategy enables efficient screening and scalable batch production of these specific moiré structures. Correlative electrostatic force microscopy (EFM) and transmission electron microscopy (TEM) reveal that only parallel-stacked flakes exhibit electrostatic contrast associated with out-of-plane polarization. EFM, Kelvin probe force microscopy (KPFM), and Raman spectroscopy further identify AB/BA stacking domains and their transition regions. To accelerate and automate moiré identification, an XGBoost-based screening workflow achieves a mean test ROC-AUC of 0.78 ± 0.14. Compared with the conventional tear-and-stack approach, this method reduces moiré preparation time by at least 40% while eliminating manual stacking, providing a simple, scalable, and broadly applicable strategy for preparing high-quality interfacial moiré superlattices in 2D materials for next-generation moiré-based electronic and optoelectronic devices.