Vapor–liquid–solid growth of large-area multilayer hexagonal boron nitride on dielectric substrates
Zhiyuan Shi, Xiujun Wang, Qingtian Li, Peng Yang, Guangyuan Lu, Ren Jiang, Huishan Wang, Chao Zhang, Chunxiao Cong, Zhi Liu, Tianru Wu, Haomin Wang, Qingkai Yu, Xiaoming Xie, Qingkai Yu, Xiaoming Xie
Abstract
Abstract Multilayer hexagonal boron nitride ( h -BN) is highly desirable as a dielectric substrate for the fabrication of two-dimensional (2D) electronic and optoelectronic devices. However, the controllable synthesis of multilayer h -BN in large areas is still limited in terms of crystallinity, thickness and stacking order. Here, we report a vapor–liquid–solid growth (VLSG) method to achieve uniform multilayer h -BN by using a molten Fe 82 B 18 alloy and N 2 as reactants. Liquid Fe 82 B 18 not only supplies boron but also continuously dissociates nitrogen atoms from the N 2 vapor to support direct h -BN growth on a sapphire substrate; therefore, the VLSG method delivers high-quality h -BN multilayers with a controllable thickness. Further investigation of the phase evolution of the Fe-B-N system reveals that isothermal segregation dominates the growth of the h -BN. The approach herein demonstrates the feasibility for large-area fabrication of van der Waals 2D materials and heterostructures.