Production and optimization of a nanosecond pulsed microplasma for atomic nitrogen generation – SPECTRON

SPECTRON is an interdisciplinary project that proposes the development of a new microplasma source of atomic nitrogen. This will be manufactured based on a micro-hollow cathode discharge (MHCD) configuration which consumes very low power and achieves huge power densities, thus enhancing the possibility to improve the dissociation of molecular nitrogen. The targeted application is the deposition on large substrates (cm scale) of hexagonal boron nitride (h-BN), a strategic material in photonics, optoelectronics, etc. The originality of the project is the first implementation of a ns pulsed high voltage with a stiff rise time (10-20 ns) which can even ignite multiple microdischarges by increasing the microplasma volume. This power supply is considered for the first time to drive MHCD. Our ambition is to achieve a strongly non-equilibrium plasma with stiff gradients of electron and reactive species densities, thus improving the plasma reactivity and decreasing the average deposition temperature. The new MHCD will be characterized in terms of stable plasma operation using different gas mixtures (N2/Ar and N2/He), materials (dielectric and electrodes), and structural geometry. The plasma physics and dynamics with emphasis on N-atom kinetics will be thoroughly investigated by means of advanced optical diagnostics such as fast imaging, space-time resolved emission spectroscopy, and ultrafast TALIF coupled to streak camera. The results obtained will be used to validate discharge kinetic and CFD models developed by the group. To perform the deposition of quality h-BN films, different precursors will be investigated, and the film quality will be assessed experimentally and correlated to the discharge properties. The consortium consists of young researchers and engineers with very complementary skills in plasma physics and applications, electrical engineering, advanced optical diagnostics, and material synthesis, making it possible to overcome the challenges of the project.