Research Data for the publication titled "Impact of irradiation conditions on the magnetic field sensitivity of spin defects in hBN nano flakes"

Abstract for the paper : We study VB− centres generated by helium focused ion beam (FIB) irradiation in thin (~70 nm) hBN nanoflakes, in order to investigate the effect of implantation conditions on the key parameters that influence the magnetic field sensitivity of VB− quantum sensors. Using a combination of photoluminescence, optically detected magnetic resonance, and Raman spectroscopy, we examine the competing factors of maximizing signal intensity through larger VB− concentration against the degradation in spin coherence and lattice quality observed at high ion fluences.Our results indicate that both the VB− spin properties and hBN lattice parameters are largely preserved up to an ion fluence of 10¹⁴ ions cm⁻², beyond which significant degradation occurs in both. At the optimal implantation dose, an AC magnetic sensitivity of approximately 1 μT / √Hz is achieved. Using the patterned implantation enabled by the FIB, we find that VB− centres and the associated lattice damage are well localized to the implanted regions. This work demonstrates how careful selection of fabrication parameters can be used to optimize the properties of VB− centres in hBN, supporting their application as quantum sensors based in two-dimensional materials.