韩国国立蔚山科学技术院Shin, Hyeon Suk团队报道了Ni(111)表面外延生长单晶六方氮化硼多层膜。相关研究成果发表在2022年6月1日出版的《自然》。
人们已经生长了大面积的二维（2D）材料单晶单分子膜，如石墨烯、六方氮化硼（hBN）和过渡金属二元化合物。hBN被认为是基于2D材料的场效应晶体管（FET）的“理想”电介质，有可能扩展摩尔定律。虽然厚度大于单层的hBN更适合用作2D半导体的基底，但仍需证明高度均匀的单晶多层hBN生长。
该文报道了用化学气相沉积（CVD）方法外延生长晶圆级单晶三层hBN。发现均匀排列的hBN岛在早期生长在单晶Ni（111）上，最终合并成单晶膜。横截面透射电镜（TEM）结果表明，通过硼在镍中的溶解，在单晶hBN膜和镍基体之间（冷却过程中）形成了Ni23B6中间层。hBN和Ni23B6以及Ni23B6和Ni之间存在外延关系。
研究还发现，hBN膜作为保护层，在氢的催化演化过程中保持完整，表明连续的单晶hBN。这种转移到SiO2（300nm）/Si晶片上的hBN起到了电介质层的作用，以减少MoS2 FET中SiO2衬底的电子掺杂。结果表明，大面积的高质量单晶多层hBN，这将为使其成为2D半导体普遍存在的基底开辟新的途径。
附：英文原文
Title: Epitaxial single-crystal hexagonal boron nitride multilayers on Ni (111)
Author: Ma, Kyung Yeol, Zhang, Leining, Jin, Sunghwan, Wang, Yan, Yoon, Seong In, Hwang, Hyuntae, Oh, Juseung, Jeong, Da Sol, Wang, Meihui, Chatterjee, Shahana, Kim, Gwangwoo, Jang, A-Rang, Yang, Jieun, Ryu, Sunmin, Jeong, Hu Young, Ruoff, Rodney S., Chhowalla, Manish, Ding, Feng, Shin, Hyeon Suk
Issue&Volume: 2022-06-01
Abstract: Large-area single-crystal monolayers of two-dimensional (2D) materials such as graphene1,2,3, hexagonal boron nitride (hBN)4,5,6 and transition metal dichalcogenides7,8 have been grown. hBN is considered to be the ‘ideal’ dielectric for 2D-materials-based field-effect transistors (FETs), offering the potential for extending Moore’s law9,10. Although hBN thicker than a monolayer is more desirable as substrate for 2D semiconductors11,12, highly uniform and single-crystal multilayer hBN growth has yet to be demonstrated. Here we report the epitaxial growth of wafer-scale single-crystal trilayer hBN by a chemical vapour deposition (CVD) method. Uniformly aligned hBN islands are found to grow on single-crystal Ni (111) at early stage and finally to coalesce into a single-crystal film. Cross-sectional transmission electron microscopy (TEM) results show that a Ni23B6 interlayer is formed (during cooling) between the single-crystal hBN film and Ni substrate by boron dissolution in Ni. There are epitaxial relationships between hBN and Ni23B6 and between Ni23B6 and Ni. We also find that the hBN film acts as a protective layer that remains intact during catalytic evolution of hydrogen, suggesting continuous single-crystal hBN. This hBN transferred onto the SiO2 (300nm)/Si wafer acts as a dielectric layer to reduce electron doping from the SiO2 substrate in MoS2 FETs. Our results demonstrate high-quality single-crystal multilayered hBN over large areas, which should open up new pathways for making it a ubiquitous substrate for 2D semiconductors.
DOI: 10.1038/s41586-022-04745-7
Source: https://www.nature.com/articles/s41586-022-04745-7