Cutting, Nanoexfoliation, and Reshaping of Multilayer MoS2 Using Atomic Force Microscopy-Based Thermomechanical Scratch

Atomically thin two-dimensional (2D) layered materials, such as molybdenum disulfide (MoS2), are candidates for next-generation nanoelectronic and optoelectronic devices. Patterning 2D materials into finite nanostructures is essential for system integration and wafer-scale manufacturing but remains a major challenge. Herein, a thermomechanical nanolithography technique is demonstrated that allows for the direct cutting, nanoexfoliation, and reshaping of multilayer MoS2 on a flexible poly(methyl methacrylate) (PMMA) substrate using a heated atomic force microscope nanotip. Using a constant force of 735 nN, a 3.8 nm-thick MoS2 was cut to form notches, nanoexfoliated, and reshaped under the heating temperatures of 120 to 170 °C induced by the great tensile stress produced via thermomechanical cleaving of the thermosensitive PMMA underneath the MoS2. However, under given parameters of 735 nN and 170 °C, the thickness of 4.4 nm was the limit thickness that MoS2 can be cut, peeled, and reshaped due to the markedly increased bending stiffness and strain energy with the enlarged thickness. The proposed direct manipulation technique of multilayer MoS2 is a promising tool for precisely tailoring nanopatterns on 2D materials for future applications in flexible nanoelectronic and optoelectronic devices.