Laser induced 2D material modification: from atomic scale to electronic scale

Background Introduction
Two dimensional materials have attracted widespread attention due to their atomic level thickness and unique properties, such as high binding energy, tunable bandgap, and new electronic degrees of freedom (valley electronics). They have many application prospects in fields such as microelectronics, nanophotonics, and nanoenergy. Various two-dimensional materials have their own advantages and disadvantages in terms of physical properties, and modifying two-dimensional materials can break through the limitations of their original properties in terms of application scope. Laser modification, as a non-contact processing technology, has the characteristics of high efficiency, high flexibility, and high spatiotemporal resolution, and is a powerful means of modifying two-dimensional materials.

Figure 1. Precise control of laser thinning of two-dimensional materials by monitoring thickness and/or self passivation

Quick News Highlights
Recently, Associate Professors Lin Linhan and Sun Hongbo from Tsinghua University published a review article on optical modification of two-dimensional materials from atomic to electronic scales in JPCC.

Figure 2. Laser assisted defect repair and exciton modulation
In the past decade, the interaction between light and two-dimensional materials has received much attention. The excitation of electrons under light can be utilized in optoelectronic and nanophotonic devices, and a profound understanding of the interactions between various light and two-dimensional materials enables researchers to change the geometric morphology, chemical composition, electronic structure, and even atomic structure of two-dimensional materials. This provides new strategies for on-demand manipulation of the optical, thermal, or electrical properties of two-dimensional materials and further expands their applications.

In the process of laser modification of two-dimensional materials, laser can directly excite electrons in the two-dimensional materials, change the electronic structure and even atomic structure of the two-dimensional materials, achieve photoconductivity control and photo induced ultrafast phase transition; It can also serve as an energy source for heat during the modification process, indirectly achieving the modification of two-dimensional materials through photothermal effects, achieving oxidation and sublimation etching of two-dimensional materials, photothermal phase transition, photothermal reduction of graphene oxide, etc; In laser-induced doping and some oxidation reactions, lasers can also assist two-dimensional materials in reacting with other substances to generate new materials with excellent performance. Focusing on graphene and transition metal chalcogenides (TMDs), the author reviewed the interactions between light and two-dimensional materials from different perspectives and discussed cutting-edge optical processing modification techniques to change the morphology and atomic structure of two-dimensional materials, and adjust their electrical and optical properties as needed; Outlined its basic mechanism, technological development, and applications, and introduced its views on future challenges and opportunities.

Source: Laser Manufacturing Network