What Has Been Achieved: We have demonstrated an efficient method to determine the symmetry and lattice constants as well as the long-range perfection of 2D materials using glancing incident electron diffraction.
Importance of the Achievement: This ARHEED methodology can be applied to other epitaxial 2D materials and to examine the wafer scale structure and perfection.
Unique Feature(s) of the MIP that Enabled this Achievement: 2DCC-MIP’s MOCVD growth of high-quality, wafer-scale monolayer epitaxial MoS2 and WS2 films.
(If Applicable) Publication: Yu Xiang, Xin Sun, Lukas Valdman, Fu Zhang, Tanushree H. Choudhury, Mikhail Chubarov, Joshua A. Robinson, Joan M. Redwing, Mauricio Terrones, Yuan Ma, Lei Gao, Morris A. Washington, Toh-Ming Lu, and Gwo-Ching Wang, Monolayer MoS2 on Sapphire: An Azimuthal Reflection High-Energy Electron Diffraction Perspective, 2D Materials 2020, https://doi.org/10.1088/2053-1583/abce08
Acknowledgments: This work is supported by the New York State’s Empire State Development’s Division of Science, Technology and Innovation (NYSTAR) through Focus Center Contract C150117 and the Penn State 2D Crystal Consortium – Materials Innovation Platform under National Science Foundation cooperative agreement DMR-1539916. Y Ma and L Gao are supported by National Key Research and Development Program of China (Grant No. 2017YFB0702100) and National Natural Science Foundation of China (Grant No. 51705017, U1706221). We thank R Xie, T Tao, and J Liu for part of data analysis and J Meese for the construction of the 3D reciprocal map of MoS2.