Optimization of Mechanical Exfoliation Parameters for 2D MoSe₂

Abstract

2D materials are widely researched due to their advanced physical, electrical, and optical properties, with promising applications in nanoelectronics. Molybdenum Diselenide (MoSe₂), a family of transition metal dichalcogenides (TMDs), is an emerging 2D material candidate composed of layered structures of molybdenum and selenium atoms. Currently available exfoliation methods to obtain 2D materials are commonly split between top-down and bottom-up methods: top-down methods focus on exfoliating 2D materials from bulk crystals while bottom-up strategies, such as Chemical Vapor Deposition (CVD), utilize atomic-level interactions to form 2D materials. This study focuses on optimizing the mechanical exfoliation parameters for high yield of 2D MoSe₂ flakes. Specifically, different types and combinations of tape (3M Scotch Tape, Nitto SWT 10+ Tape, and Revalpha 3195VS (4M) Thermal Release Tape) were tested alongside thermal treatment ranging from 30℃ to 170℃ and tape filtration. Optical microscopy revealed that Revalpha 3195VS (4M) Thermal Release Tape produced the largest flake size with slight residue as compared with the other two. It was also found that using Revalpha 3195VS (4M) as an intermediary step or thermal treatment at high temperatures helps to increase flake sizes among all tapes, but leaves residue stains on flakes. Finally, two filtrations yielded the highest flake sizes.The results demonstrate the improved parameters of mechanical exfoliation for larger and higher yields of 2D flakes, which can be utilized for nanoelectronics.