Damage-free transfer mechanics of 2-dimensional materials: competition between adhesion instability and tensile strain

Abstract

The transfer of two-dimensional (2D) materials is crucial to the realization of 2D material-based devices for practical applications. The thinness of 2D materials renders them prone to mechanical damage during the transfer process and to degradation of their superior electrical and mechanical properties. Herein, the mechanisms involved in the damage of chemical vapor deposition-grown graphene (Gr) and MoS2 are investigated during a roll-based transfer process. We identify two different damage mechanisms, i.e., instability-induced damage and tensile strain-induced damage. The two mechanisms compete, depending on the thickness of the transfer medium, and induce dissimilar damage. By minimizing these two mechanisms, we realize and demonstrate the damage-free transfer of 2D materials. The sheet resistance and mobility of transferred Gr are 235 ± 29 Ω sq–1 and 2250 cm2 V–1 s–1, respectively, with no microscopic cracks or tear-out damage. We observe instability-induced damage to be ubiquitous in monolayer MoS2, thin metals, and thin oxide films. By understanding the instability-induced damage mechanism, a broad range of 2D materials and thin films can be transferred without mechanical damage. Damage-free transfer will contribute to the high-yield fabrication of 2D material-based electronic devices.