New progress and prospects of mechanical exfoliation technology of two-dimensional materials

Since the monolayer graphene was first obtained in the year of 2004, mechanical exfoliation technique has been widely used to prepare various two-dimensional materials such as transition metal dichalcogenides and black phosphorus. Among a variety of preparation techniques of two-dimensional materials, mechanical exfoliation technique shows advantages in its simplicity and universality. More importantly, the exfoliated two-dimensional samples are the ideal ones for many novel phenomena. This paper introduces the background of mechanical exfoliation technique and summarizes the problems of conventional mechanical exfoliation technique in the development of two-dimensional materials. In order to solve the problems of low efficiency and small sample size of conventional mechanical exfoliation technique, some modified mechanical exfoliation techniques have been developed, such as oxygen-plasma-assisted exfoliation method and gold-film-assisted exfoliation method. As a commonly used “top-down” preparation method, the new exfoliation technology is still full of vitality in basic research and application of two-dimensional materials. In the future, larger size and higher quality will be the development direction of exfoliation technology.