Exploring the properties of light-assisted nanoscale defect formation in hexagonal boron nitride

Engineering of two-dimensional (2D) materials by modifying edges, creating folds, vacancies or by doping is advantageous to tailor their performance for targeted applications, such as in electronics or catalysis. However, exploring the impact of such defects on the local properties of the layer in which they are introduced is challenging as it requires functional measurements with high lateral resolution and high sensitivity.
Here we show that nanoscale defects can controllably be introduced in the hexagonal boron nitride (h-BN) lattice using the tip of an atomic force microscope (AFM). More specifically, we investigate the dual effect of tip-sample interaction and light on local defects formed in h-BN. We discuss changes in morphology and lattice vibrations observed with different environmental conditions, h-BN thicknesses, light power density and duration of exposure. We show that defects formed under inert environment exhibit changes in morphology, accompanied with the apparition of new IR bands in their spectra signature when exposed to air. This work brings about new means to bridge the gap between conventional characterization of 2D materials and atomistic computational models in view of reaching a deeper understanding of chemisorption and reactions at or near defect sites.