Laser induced surface oxidation of 2D breathing kagome lattice material Nb3Br8

Two-dimensional materials, known for their tunable properties through methods like chemical doping and strain, are widely used in electronics and optics research and applications. In this work, we perform laser-induced surface modification on exfoliated niobium bromide (Nb3Br8), a 2D quantum material with a breathing kagome lattice featuring topologically protected flat bands. A 532 nm laser with a micron-sized beam spot and power of 6 mW is used to create an initial defect, leading to the formation of hexagonal shaped surface modifications once the substrate is heated above 500 K. Imaging using optical microscopy, atomic force microscopy, and scanning electron microscopy confirm the hexagonal shape of the surface modification, which can be correlated to the crystalline structure of the material. Electron diffraction spectroscopy indicates the signature of oxides forming on the modified surface. Additionally, Raman maps show the emergence of a peak and increased background signal within the hexagonal shapes, suggesting oxides bonding to the lattice. Our findings provide a method for selectively oxidizing the surface of Nb3Br8 in a controlled and patternable fashion, which could lead to tailored electronic and optical properties in next-generation devices.