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.