State-of-the-art wafer-scale high-mobility graphene transistors reach an electronic mobility of 10⁴ V.s/cm² using Aluminum Oxyde dielectrics, which is close to the minimal requirement to observe graphene electroluminescence. Using hexagonal Boron Nitride as dielectric is sufficient to allow the breakthrough in performances. Unfortunatly, hBN is notoriously difficult to synthetize, and for high-mobility graphene transistors, it originates in small and expensive quantities only allowing the fabrication of single handcrafted devices. The goal of this workpackage is therefore to develop a more scalable route for the fabrication of high-quality hBN more compatible with wafer-scale fabrication processes. LMI and INSA collaborate to this goal. A great advantage of this fabrication route is the possibility to use hBN with various phonon anharmonic damping (which presumably plays a key rôle in graphene electroluminescence), thus allowing the experimental investigation of electroluminescence microscopic mechanism.