Fabrication of Defective Single Layers of Hexagonal Boron Nitride on Various Supports for Potential Applications in Catalysis and DNA Sequencing

Two-dimensional hexagonal boron nitride (hBN) has been shown to be a suitable substrate and gate material for high-performance graphene electronics and has been proposed for applications in catalysis and DNA sequencing. This study explores how highly charged ions can be used for defect engineering, i.e., to locally induce modifications in single layers of hBN. For this, we irradiated single layers of hBN on SiO2, Mo foil, and Ir(111) with highly charged Xeq+ ions of different charge states (up to q = 40) at a fixed kinetic energy of 260 keV. The ion-induced nanoscaled modifications are analyzed as a function of the charge state using atomic force microscopy in the friction force mode and secondary-ion mass spectrometry. The data show that a charge state of more than q = 28 corresponding to a minimum potential energy of 15-17 keV is sufficient to achieve defect creation via electronic excitation. This is higher in comparison to graphene on SiO2 (similar or equal to 12 keV), which opens up the possibility of selective defect creation in graphene/hBN heterostructures. Our results are further corroborated by two-temperature model calculations showing good agreement with the experiment. On the basis of our results, we propose that the intense electronic excitation induced by the highly charged ion leads to sublimation of the material from nanometer-sized regions of the single-layer hBN sheet.