Large-Scale and Ultraclean Dry Transfer of Two-Dimensional Materials via Liquid Nitrogen-Assisted Cryogenic Exfoliation.

Abstract

Transition metal dichalcogenides (TMDCs) hold significant promise in constructing next-generation high-performance electronic devices, potentially extending Moore's law and enabling the realization of three-dimensional integrated circuit architectures. However, realizing this potential depends critically on developing a reliable method to transfer TMDCs from a growth substrate to desirable surfaces. Here, we report a dry-transfer strategy of liquid nitrogen-assisted cryogenic exfoliation to achieve large-scale and superclean transfer of TMDCs. Benefited from the synergistic effect of liquid nitrogen-induced exfoliation and protection of hafnium oxide, the transferred TMDCs are free from polymer residues and show excellent electrical property, and taking n-type single-crystal molybdenum disulfide as a demonstration, the transferred TMDC exhibits high carrier mobility up to 38.4 cm² V^-1 s^-1. Moreover, this transfer method shows versatile capabilities in transferring monolayer and multilayer TMDCs and constructing bi- and trilayer heterostructures. Therefore, our proposed transfer methodology promises the integration of TMDCs into future, ultimately scaled-down, electronic device technologies.