Optical Modification of Two-Dimensional Materials: From Atomic to Electronic Scale

Two-dimensional (2D) materials have attracted much attention because of their atomic-thin thickness and unique properties, such as high binding energy, tunable band gap, and new electronic degrees of freedom (valleytronics). They have found many applications in microelectronics, nanophotonics, nano energy, and so on. In the past decade, various 2D devices have been developed, including field effect transistor (FET), nano light source, photodetector, supercapacitors, etc. However, the application of 2D materials is still limited by their intrinsic properties, e.g., the low carrier concentration, high contact resistance at heterogeneous interface, and the challenge of thickness control in transition metal dichalcogenides. It remains an alluring perspective to tune the geometry and electronic and photonic properties of 2D materials on demand. Specifically, laser modification is a contactless processing technique with high accuracy, high efficiency, and versatility due to the flexibility to manipulate light at high spatiotemporal resolution. Here, we review the light–matter interaction during laser modification of 2D materials. The cutting-edge optical techniques to modify the geometry, the composition, and the electronic structure are summarized. Moreover, we discuss the applications of such optical techniques in various 2D devices. The understanding of the underlying physics and the tunable material properties will benefit future technological innovation in laser processing and fabrication of high-performance 2D devices in microelectronics and nanophotonics.