Stick-Slip Delamination of Monolayer MoS2 from SiO2 under Ambient Humidity.

Delamination of two-dimensional (2D) materials from substrates plays a key role in 2D material transfer processes and applications in tribology and printing. Here, we studied the delamination of monolayer MoS2 from a SiO2 substrate at ambient relative humidity, using atomic force microscopy and force-distance spectroscopy. In contrast to dry conditions, tip retraction at ambient humidity is dominated by capillary forces between the tip and MoS2 and exhibits an extended force plateau of about 10-15 nm that is decorated by oscillatory sawtooth features. These oscillations indicate a stick-and-slip propagation of a circular delamination front between the MoS2 and SiO2 during lifting of the membrane by the tip, when intercalation of water reduces MoS2-substrate adhesion. This stick-slip delamination process is consistent with depinning from a spatially heterogeneous adhesion landscape, likely influenced by the nanoscale roughness of SiO2.