Twisted epitaxy of gold nanodisks grown between twisted substrate layers of molybdenum disulfide
Yi Cui, Yi Cui, Jingyang Wang, Yanbin Li, Yecun Wu, Emily Been, Zewen Zhang, Jiawei Zhou, Wenbo Zhang, Harold Y. Hwang, Robert Sinclair, Yi Cui, Yi Cui
Abstract
We expand the concept of epitaxy to a regime of “twisted epitaxy” with the epilayer crystal orientation between two substrates influenced by their relative orientation. We annealed nanometer-thick gold (Au) nanoparticles between two substrates of exfoliated hexagonal molybdenum disulfide (MoS 2 ) with varying orientation of their basal planes with a mutual twist angle ranging from 0° to 60°. Transmission electron microscopy studies show that Au aligns midway between the top and bottom MoS 2 when the twist angle of the bilayer is small (<~7°). For larger twist angles, Au has only a small misorientation with the bottom MoS 2 that varies approximately sinusoidally with twist angle of the bilayer MoS 2 . Four-dimensional scanning transmission electron microscopy analysis further reveals a periodic strain variation (<|±0.5%|) in the Au nanodisks associated with the twisted epitaxy, consistent with the Moiré registry of the two MoS 2 twisted layers.